Bulletin of the American Physical Society
2005 APS March Meeting
Monday–Friday, March 21–25, 2005; Los Angeles, CA
Session R1: Poster Session III 
Hide Abstracts 
Room: LACC Exhibit Hall 1:004:00pm 

R1.00001: GENERAL II POSTER SESSION 

R1.00002: Electrogravitational Repulsion as an explanation for Various Astrophysical Phenomena J. Montgomery, P. Russell Recent analysis of carefully timed radio telemetry signals of several space probes deployed by NASA show that they are being slowed by an anomalous constant acceleration with an average magnitude of approximately $8\times 10^{10}m/s^2$, oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the spacetime continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to relate closely to the wavelength $\lambda _{\max } $at which the sun emits radiation most intensely. The evidence that supports this hypothesis also provides the solution to various other astrophysical and cosmological effects that exhibit anomalous gravitational behavior. Calculations using the data concerning the four probes result in the formula $a=\hbar \frac{c^2}{\lambda _{\max } }$ which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant $k$. The evidence also gives a strong indication that light, in addition to its particlewave nature, also has field characteristics. [Preview Abstract] 

R1.00003: Scalability of Parallel DiscreteEvent Algorithms M.A. Novotny, Gyorgy Korniss We continue our previous studies [14] of scalability of parallel discrete event simulations (PDES). Previously, ignoring communication overhead, we have shown that ALL short ranged PDES can be made perfectly scalable [2]. These works simulated the PDES simulations and used ideas of non equilibrium surface growth to analyze the virtual time surfaces of PDES. We present results that expand on these results in two ways. First, we also include communication times in the simulations. For shortranged simulations we observe perfect scalability including communication times. Second, we study relaxation of the shortranged requirement. Rather we limit the number of sites each processing element can communicate with. Hence we study scalability of systems with sparse communication patterns.\newline [1] G. Korniss et al, Phys. Rev. Lett., vol. 84, p. 1341 (2000).\newline [2] G. Korniss et al, Science, vol. 299, p. 677 (2003).\newline [3] A. Kolakowska, et al, Phys. Rev. E, vol. 68, 046705 (2003).\newline [4] L.N. Shchur and M.A. Novotny, Phys. Rev. E, vol. 70, 026703 (2004). [Preview Abstract] 

R1.00004: The December, 1931 absorption experiments by Irene and Fredrick JoliotCurie using Po Be, PoB and PoLi sources to study penetrating radiation Stephen Shafroth The December, 1931 absorption experiments by Irene and Fredrick JoliotCurie using Po Be, PoB and PoLi sources to study penetrating radiation S.M. Shafroth, Physics and Astronomy Department, University of North Carolina at Chapel Hill 275993255, shafroth@physics.unc.edu. The experimental arrangement including the Hoffman electroscope radiation detector and samples of the raw data are shown.$^{1}$ The emitted neutrons were interpreted as very high energy penetrating gammas. The exponential decay of detected radiation with thicknesses of Pb from 1.5 5 cm are shown. I. Curie concludes, based on current knowledge of absorption coefficients vs gamma energy, that the gamma energy from PoBe was 1520 MeV. However cloud chamber experiments had shown that the ``penetrating radiation'' could eject protons from paraffin with energies of 4.5 and 2 MeV in the case of Be and B respectively. If the ejection mechanism were the Compton effect, the gamma energies had to be 50 and 35 MeV respectively. Finally they conclude that the discrepancy in gamma energies could be ``due to the uncertainties.'' \newline 1. Comptes Rendus de l'Academie des Sciences, S\'{e}ance du 28 Decembre 1931 [Preview Abstract] 

R1.00005: ChemMatCARS: A National Synchrotron Facility for Chemistry and Materials Research Binhua Lin, David Schultz, Mati Meron, Tim Graber, Jeff Gebhardt, David Cookson, Myungae Lee, P. James Viccaro ChemMatCARS is a national synchrotron xray facility dedicated primarily to static and dynamic condensed matter chemistry and materials science. The facility makes use of highly intense x ray radiation, tunable over the range of 6 to 32 keV. Key experimental capabilities include timeresolved measurements to the µsec time domain, element, valence specific resonant diffraction, and highenergy xray scattering. A list of currently available techniques includes the following: surface sensitive xray scattering to investigate dynamical and structural properties of surfaces and interfaces in a variety of liquid and solid systems, small and wideangle xray scattering from condensed matter for the study of polymers, colloids, composite materials, fiber (structure and processing), and crystallization kinetics, microcrystal diffraction to study charge densities, distributions and mixed valence systems, time resolved crystallography to probe transient species in chemically excited states and anomalous scattering techniques which make use of elemental absorption edges. [Preview Abstract] 

R1.00006: APPLICATIONS 

R1.00007: Magnetoelectric Composite Based Microwave Attenuator A. S. Tatarenko, M. I. Bichurin, A. A. Charlamov, D. A. Filippov, G. Srinivasan Ferriteferroelectric composites are magnetoelectric (ME) due to their response to elastic and electromagnetic force fields. The ME composites are characterized by tensor permittivity, permeability and ME susceptibility. The unique combination of magnetic, electrical, and ME interactions, therefore, opens up the possibility of electric field tunable ferromagnetic resonance (FMR) based devices [1]. Here we discuss an ME attenuator operating at 9.3 GHz based on FMR in a layered sample consisting of lead magnesium niobatelead titanate bonded to yttrium iron garnet (YIG) film on a gadolinium gallium garnet substrate. Electrical tuning is realized with the application of a control voltage due to ME effect; the shift is 015 Oe as E is increased from 0 to 3 kV/cm. If the attenuator is operated at FMR, the corresponding insertion loss will range from 25 dB to 2 dB. 1. S. Shastry and G. Srinivasan, M.I. Bichurin, V.M. Petrov, A.S. Tatarenko. \textit{Phys. Rev. B}, 70 064416 (2004).  supported by grants the grants from the National Science Foundation (DMR0302254), from Russian Ministry of Education (Å023.4278) and from Universities of Russia Foundation (UNR 01.01.026). [Preview Abstract] 

R1.00008: Applying statistics of random processes to prediction of weathering degradation and service life Stuart Croll, Brian Hinderliter Predicting the service lifetime of any material is very important. One of the difficulties is relating individual, nanoscale, degradation events to the eventual deterioration in performance, which samples material properties at vastly larger scales. The Central Limit theorem provides an asymptotic approximation to the kinetics of how coating topology, or bulk morphology, changes after long term degradation during weathering. Results may then be translated, via wellknown models, into the deterioration of properties such as reflectance, fracture strength, surface wetting, color etc. Thus service lifetime may be related to material structure. There is potential for using properties that permit nondestructive monitoring, e.g. reflectance, to predict other properties that would necessitate destructive evaluation, e.g. fracture strength. In addition, this approach may have much broader application to other situations where an eventual condition is the result of repeated, random events. [Preview Abstract] 

R1.00009: Applications of the remarkable pressure effect on electron beam production by cooled LiNbO3 crystals in dilute gases Stephen Shafroth, James Brownridge In 2001 we reported on focused, electron beams accelerated away from cylindrical LiNbO$_{3}$ crystals in dilute gas on cooling with the  z base exposed. These beams consisted of clusters of electrons arising from positive ion bombardment of the crystal on cooling. Even though the energy of the clusters of electrons in the beam changes with time and crystal temperature, it is nearly constant over periods of a few minutes. Remarkably, the maximum electron energy is strongly pressure dependent (more than a factor of two.) Here we show how this allows production of maximum energy bremsstrahlung$^{1}$; how the pressure effect influences electron beam energy in transport through thin tubes and how it effects electron beam intensity and focusing. 1. J. D. Brownridge and S. M. Shafroth, Appl. Phys. Letts. 85, 1298 (2004) and http://www.binghamton.edu/physics/brownridge.html [Preview Abstract] 

R1.00010: Electrical properties of Si nanocrystals capped with SiO2/Si3N4 for nonvolatile memory JungMin Kim, E. K. Lee, Y. Khang, EunHye Lee, KyoYeol Lee, JooHyun Lee, C. J. Kang, YongSang Kim Electrical properties of Si nanocrystals (NCs) were analyzed with respect to the shell formation of NCs. The Si nanocrystal samples produced by pyrolysis and laser ablation methods were followed by sharpening oxidation steps. In these steps Si NCs are capped with a thin oxide or nitride layer of 12nm thickness for isolation and the size control. It also affects the interface states of NCs, resulting in the change of electrical properties. To clarify this effect, conventional CV, IV and charge retention time measurements were performed on a MOS capacitor structure. Using scanning probe microscopy (SPM), we observed local properties of a capped Si nanocrystal. These results were analyzed for the size, density and shell materials of NCs. We also measured the temperature dependence of electrical properties of Si NCs. [Preview Abstract] 

R1.00011: Fano quadrupole in a nanoscale ring Arkady Satanin, Yong Joe, Gerhard Klimeck In solid state systems such as AharonovBohm (AB) rings, twodimensional electronic waveguides, and barriers, interference of a localized wave with propagating states produces Fano resonances in the conductance. The scattering amplitude near a Fano zeropole pair behaves like the amplitude of a dipole when the pole and the zero play the roles of a particle and an antiparticle, respectively [1]. This separate Fanodipole has been already observed in the AB ring with an embedded quantum dot (QD) [2]. In the present work, we examine new effects on the collision of Fano dipoles and its manifestation in the transmission. The numerical results for a realistic AB ring with two embedded QD's will be presented. We show that the two Fanodipoles form a new quasiparticle, which behaves as a coupled object  the Fano quadrupole. This property gives an additional possibility of manipulating transmission resonances (a collapse of particle and hole) in a nanoscale ring by changing the parameters of the system. We discuss an analogy of Fano collision in an AB ring and a $\Gamma {\rm X}$ barrier [3]. [1] Z. Shao \textit{et al.}, PRB \textbf{49}, 7453 (1994). [2] K. Kobayashi,\textit{ et al.} PRL, \textbf{85}, 256806 (2002). [3] R. C. Bowen,\textit{ et al.} PRB \textbf{52}, 2754 (1995). [Preview Abstract] 

R1.00012: Near infrared intersubband transitions in deltadoped InAs/AlSb multiquantum wells Shigehiko Sasa, Yoji Nakajima, Masato Nakai, Masashi Furukawa, Masataka Inoue, Diane Larrabee, Junichiro Kono Intersubband transitions (ISBTs) in Si doped narrow InAs/AlSb multiple quantum wells (MQWs) were investigated for well widths, $d$, ranging from 5 nm down to 1.8 nm with 10, 20 or 60 periods. As the well width decreased, the ISBT signal of the MQWs decreased. However, it persisted down to $d$ = 2.1 nm with a sheet doping density in each quantum well of 9 x 10$^{12}$ cm$^{2}$ and 60 periods. The ISBT signal observed for $d$ = 2.1 nm was peaked at an energy of 670 meV at 77K. A large linewidth increase was also observed for the narrowest wells ($d \quad \le $ 3 nm). In order to study the origin of the linewidth broadening, we measured the electron mobility of the samples and found that the mobility showed $d^{6}$ dependence for $d \quad \le $ 3 nm. We show that the linewidth broadening is well explained by the reduction in the mean free time as the well width decreased. [Preview Abstract] 

R1.00013: Patterning Process of MembraneAssociated Proteins on a Solid Support with Geometrical Grooves Cherlhyun Jeong, Taeyoung Yoon, SinDoo Lee, Joon Heon Kim, Myung Chul Choi, Mahn Won Kim We have shown a patterning process of membraneassociated proteins through spontaneous assembling of the lipid anchors on a solid support with geometrical grooves. The lipid anchors possessing unbalanced effective molecular shapes are assembled near geometrical groove structures so as to minimize the free energy of elastic distortions. The specific patterning of the lipid anchors and the membraneassociated proteins can be attained without disturbing twodimensional lateral fluidity of a supported membrane. Our patterning concept of the supported membrane would be applicable for devising biosensors and protein chips. [Preview Abstract] 

R1.00014: Visualizing charge injection in a DNA molecule and DNAprotein complexes with scanning probe microscopy NamJoo Lee, Kyung Ah Yoo, Jae Woo Yoo, Yong Sang Kim, Chi Jung Kang Scanning probe microscopy (SPM) with a conducting tip is performed on single, doublestranded DNA molecules and on DNAprotein complexes. The applied bias voltage dependence of each molecule on a silicon substrate was monitored first to clarify the DNAsubstrate interaction and to subtract the background effects in our experiment. After charge injection from the tip to the sample through the voltage stress to a local area of DNA molecule, apparent height difference was measured and compared with that before stressed one. Similar experiments were done with different bias polarities and with sequential stress steps. Injection efficiency with respect to the conformational change of DNA molecules was also monitored. The physical and electrical properties of the DNAprotein complexes were measured by local probing around the proteinDNA binding sites using SPM. [Preview Abstract] 

R1.00015: Tuning of thin film composite nanofiltration membranes containing poly(vinylidene fluoride)gpoly(oxyethylene) methacrylate Ayse Asatekin, Ariya Akthakul, Richard F. Salinaro, Anne M. Mayes Thin film composite nanofiltration membranes have applications in many fields ranging from water purification to molecular separations. The microphase separation of amphiphilic graft copolymers consisting of a hydrophobic poly(vinylidene fluoride) (PVDF) backbone and poly (oxyethylene) methacrylate (POEM) sidechains, PVDFgPOEM, was previously employed to create nanochannel membranes with subnanometer size selectivity [1]. Here we explored means of tuning the molecular size cutoff of these membranes by a simple processing approach: Widening of the hydrophilic nanochannels by the addition of poly(ethylene oxide) (PEO) to the casting solution. PEO is subsequently removed by the immersion of the membrane in a solvent such as isopropanol. [1] A. Akthakul, R.F. Salinaro, A.M. Mayes, Macromolecules 2004, 37, 76637668 [Preview Abstract] 

R1.00016: Microfabrication of Organic Devices Shabana Sultana Conducting polymers have unique optical, electrical and mechanical properties. Their combined plastic like property with the additional advantage of conductivity either in the metallic or semiconducting regimes have opened up many new possibilities for microelectronic devices. Hence, fabrication of organic microdevices was the focus of this experiment. Conducting polyaniline with different doping has been used. It is an experimental material developed by Crosslink Polymer Research, a Division of Lumimove, Inc. The technique involves patterning of the polymer on the substrate, silicon wafer. The patterned polymer is in the form of arrays consisting of square pads ranging from 15micro m in length to 125micro m. Since, the nature of the surface properties is critical for functioning of electronic products, their surface properties were studied by scanning electron microscope and atomic force microscopy. Electrical characterization has also been performed on these devices using the 4probe method. From preliminary results, a linear curve is expected for IV characterization. [Preview Abstract] 

R1.00017: Fault Tolerance Calculations for Quantumdot Cellular Automata devices Mahfuza Khatun, Travis Barclay, Ioan Sturzu A numerical study of the joint influence of temperature and positional defects on Quantumdot Cellular Automata (QCA) operation will be presented. The statistical model that has been introduced, simulates the random distribution of positional defects of the dots within cells, and of cells within arrays. We have studied specific clocked and nonclocked QCA devices using both a full basis quantum statistical method and Intercellular Hartree Approximation for different temperatures. Parameters such as success rate and breakdown displacement factor were defined and calculated numerically. Results show the thermal dependence of breakdown displacement factor of the QCA devices. The breakdown displacement factor decreases with the temperature. The work has been supported by the Indiana 21$^{st}$ Century Research and Technology Fund ({\#} 04492) [Preview Abstract] 

R1.00018: Localized electrical properties of individually charged silicon nanocrystals embedded in a SiO2 layer J. M. Son, E. K. Lee, J. M. Kim, S. H. Jin, Eunhye Lee, Kyoyeol Lee, Joohyun Lee, Y. Khang, Y. S. Kim, C. J. Kang Electrical properties of silicon nanocrystals (NCs) were characterized by scanning probe microscopy (SPM). The NC samples were produced by pyrolysis and laser ablation methods and followed by a process for sharpening steps to improve the size uniformity and to isolate each NC. Direct injection and removal of charge from the conducting tip to a NC was carried out and the measurement of very small amount of capacitance variation was performed. The results were analyzed with respect to the shape, size and the materials of capping shell of NCs and indicated the charging characteristics of NCs. To find out the effect of interface states reduction through a sharpening oxidation, we observed CV dependence of NCs with different capping shells and the results were compared with those of conventional MOS capacitor. [Preview Abstract] 

R1.00019: Raman spectra of suspended individual single wall carbon nanotubes using a tunable excitation laser. Hyungbin Son, E.B. Barros, Ge. G. Samsonidze, Jing Kong, M.S. Dresselhaus Due to the enhanced Raman signal from suspended individual single wall carbon nanotubes (SWNTs), a detailed study of weak Raman features, such as the intermediate frequency modes (IFMs), became possible at a single nanotube level (1). Using a tunable excitation laser, the resonance window, the dispersion, and the resonance mechanism of these Raman features are studied in detail. This information will be correlated to the (n,m) chirality of the SWNTs. (1) Hyungbin Son, et al. \textit{Appl. Phys. Letts}, \textbf{2004}, 85, 20, 4744. [Preview Abstract] 

R1.00020: SelfAssembly of Nanoparticle Wires Jiajie Diao, Jaime Hutchison, Jianwei Sun, Mark Reeves We present a technique to make lowdimensional nanoparticle structure, EvaporationDriven Colloidal Deposition (EDCD), which is developed from a similar deposition method for preparing nanoparticle thin films. A substrate immersed into a nanoparticle suspension is gradually exposed to air by evaporation. Due to the interface forces, nanoparticles at the liquidairsubstrate interface subsequently deposit on the liquidair interface along the airliquid boundary. While uninterrupted evaporation results in a continuous nanoparticle thin film, evaporation followed by rapid removal of a small quantity of the suspension leads to the formation of a nanparticle wire, and successive removal of the suspension leads to a stepwise formation of nanoparticle wires on the substrate. The width of each wire depends on the deposition time, whereas the distance between two adjacent wires is controlled by the volume of the suspension removed at each step. This method is suitable for both metallic and nonmetallic nanoparticles. The current to voltage response and its temperature dependency of gold nanoparticle wires made by EDCD are shown. [Preview Abstract] 

R1.00021: Novel effect of thickness of separate confinement heterostructure layer Gagik Shmavonyan Experiments show that the layer of separate confinement heterostructure has a significant influence on the emission spectrum of semiconductor optical amplifiers/superluiminescent diodes. Reducing the thickness of layer of separate confinement heterostructure at pside could improve the uniformity of carrier distribution among multiple quantum wells. With three In$_{0.67}$Ga$_{0.33}$As$_{0.72}$P$_{0.28}$ quantum wells near the nside, when the thickness of the layer of separate confinement heterostructure changes from 120 nm to 30 nm, the operation current for semiconductor optical amplifiers/superluiminescent diodes to exhibit the full width at half maximum spectral width of above 270 nm could be reduced from 500 to 160 mA. The layer of separate confinement heterostructure is found to have a significant influence on the carrier distribution among the multiple quantum wells and the emission spectrum semiconductor optical amplifiers/superluminescent diodes. [Preview Abstract] 

R1.00022: Design of Microlasers and Beam Splitters using chaotic ray dynamics German A. LunaAcosta, J. Antonio MendezBermudez, Oliver Bewdix Abstract. We consider chaotic waveguides formed by single or multiple 2D \textit{chaotic cavities} connected to leads. The cavities are chaotic in the sense that the ray/particle dynamics within them is chaotic. Specifically the phase space is mixed, with chaotic regions surrounding stable islands where motion is regular. Stable islands are inaccessible to the incoming rays/particles. In contrast, incoming plane waves can \textit{dynamically tunnel} into them at a certain set of discrete values of frequency/energy. The support of the corresponding quasibound state is along the trajectories of periodic orbits trapped within the cavity. We take advantage of this difference in the ray/wave behavior to demonstrate how chaotic waveguides, electromagnetic or electronic, can be used to design beam splitters and microlasers[1]. We also present some preliminary experimental results in a microwave realization of a chaotic waveguide. \newline \newline [1] J. A. M\'{e}dezBerm\'{u}dez, G. A. LunaAcosta, P. Seba, and K. N. Pichugin, Phys. Rev. B \textbf{67}, 161104(R) (2003). [Preview Abstract] 

R1.00023: Selective, Controllable, and Reversible Aggregation of Polystyrene Latex Microspheres via DNA Hybridization Phillip Rogers, Carl Bauer, Stephen Vanderet, Daniel Hansen, Antoine Calvez, Jackson Crews, James Lau, Alistair Wood, Khodadad Dinyari, Brad Roberts, Eric Michel, David Pine, Peter Schwartz The directed three dimensional selfassembly of microstructures and nanostructures through the selective hybridization of DNA is the focus of great interest toward the fabrication of new materials. Single stranded DNA is covalently attached to polystyrene latex microspheres and functions as a ``smart Velcro'' by only bonding to another strand of DNA of complementary sequence. The attached DNA increases the charge stabilization of the microspheres and allows controllable aggregation of microspheres by hybridization of complementary DNA sequences. The process is reversible by heating, with a characteristic ``aggregate dissociation temperature'' that is dependent on salt concentration, and the evolution of aggregate dissociation with temperature is observed with optical microscopy. [Preview Abstract] 

R1.00024: GENERAL THEORY (THEORETICAL METHODS) 

R1.00025: Ground State of the FalicovKimball Model William J. Massano, Jay D. Mancini, Vassilios Fessatidis, Samuel P. Bowen Here we wish to consider the ground state of the spinless FalicovKimball model, which represents one of the few mathematical models that describe strong electronelectron correlations and is exactly solvable (in the infinite dimensional limit). The model itself describes the order disorder transitions of annealed binary alloys wherein itinerant electrons interact locally with static ions. A Coupled Cluster Method approach will be used to evaluate the ground state properties of the system. Here the wave function for the many particle interacting system is given by $\left\vert \Psi\right\rangle =e^{s}\left\vert \Psi_{0}\right\rangle $ where the operator $S$ represents all one particle, two particle, \ldots, etc.~interactions. A set of non linear equations is generated from the matrix elements $E_{0} =\left\langle \Psi _{0}\right\vert H\left\vert \Psi_{0}\right\rangle $ and $\left\langle \Psi _{0}\right\vert H\left\vert \Psi_{n}\right\rangle =0$ from which the ground state energy $E_{0}$ may be computed. [Preview Abstract] 

R1.00026: Increasing the coupling constant range of perturbative approximations for ground state and excited state energies for the anarmonic oscillator Samuel Bowen, Jay D. Mancini, Vassilios Fessatidis A perturbative interpolation scheme related to Feenberg's earlier perturbation theory ideas has been applied to the ground state and excited state energies of the anharmonic oscillator. For each energy level a single parameter can be adjusted to increase the close agreement between the interpolated energy level and the ``exact'' energy (determined by direct diagonalization of a large Hamiltonian matrix). The adjustment of this parameter can increase the range of agreement by a factor of 1000 in the coupling constant over the range in which standard perturbation theory applies. Several examples of extended agreement for different states will be presented and an attempt to determine this adjustable parameter apriori using small matrix truncations will be described as will applications of these ideas to other simple Hamiltonians. [Preview Abstract] 

R1.00027: Monte Carlo Simulations of Amorphous Silicon Dave Gilson, Blair Tuttle A computational algorithm has been developed for simulating amorphous silicon. The algorithm employs a Monte Carlo bond switching scheme to anneal and cool the system without creating dangling bonds. A variety of topological parameters are examined as a function of simulation cell size. [Preview Abstract] 

R1.00028: ThreeDimensional Ising Model: Recalcuting the Finite Size Scaling J. Rufinus We have performed extensive calculations of finite size scaling in the threedimensional Ising model using a cluster of computers. Monte Carlo calculations with nearest neighbor interactions are used. Periodic boundary conditions are imposed on the model with more than 128 lattices in each site. Data taken over several thousand runs are collected and averaged. We show results for the energy, magnetization, and specific heat. Estimation for the critical coupling is also given. [Preview Abstract] 

R1.00029: Coupled Cluster Approximation to the \emph{tJ} Model Jay D. Mancini, Vassilios Fessatidis, Samuel P. Bowen We study the ground state of the onedimensional \emph{tJ} model with a single hole using the well known Coupled Cluster Method (CCM). The Hamiltonian includes a kinetic energy term \emph{t} which represents electron hopping from atomic site to atomic site with a probability which is proportional to the overlap of their (localized) wave functions. There is also an intraatomic Coulomb energy $\emph{U}$ taken to be large so that the region of parameter space of interest is $t/U\ll1$. The CCM is a wellknown scheme for evaluating manyparticle systems wherein an operator $S$ is introduced as $\left\vert \Psi\right\rangle =e^{s}\left\vert \Psi_{0}\right\rangle $ and represents the manyparticle excitations of the system. A set of nonlinear equations are then generated from $\left\langle \Psi_{0}\right\vert H\left\vert \Psi _{n}\right\rangle =0$ and $\left\langle \Psi_{0}\right\vert H\left\vert \Psi_{0}\right\rangle =E_{0}$ in which the ground state energy may then be calculated. [Preview Abstract] 

R1.00030: Timedependent DMRG study of the Hubbard model in strong electric fields Takashi Oka, Ryotaro Arita, Hideo Aoki In order to explore transport properties of a correlated electron system out of equilibrium, we have studied transient behaviors of the onedimensional Mott insulator in strong electric fields with the timedependent DMRG method. The strong field drives the system away from the insulating ground state to a nonlinear regime, which is caused by successive nonadiabatic quantum tunneling processes. The decay rate of the ground state is estimated from its temporal evolution, and the nonequilibrium phase diagram is obtained. An intermediate phase is found where the dielectric breakdown is suppressed by a strong relaxation effect induced by the electronelectron interaction preventing charge excitations from moving freely. We have also looked into optical responses in the nonlinear regime by calculating the transient correlation function. [Preview Abstract] 

R1.00031: The electronic structure of PrT2B2C (T=Co,Ni and Pt) : A Tight Binding  Extended Huckel D.H. Galvan, C. Samaniego, A. PosadaAmarillas, A. Duran, F. Morales, R. Escudero The calculations reported in this work were carried out by means of the tightbinding method within the Extended Huckel framework using {\sc YAeHMOP} computer package with forbitals. The calculated energy bands indicate that the three compounds under investigation show metallic behavior mainly caused by the dstates of the $\rm \bf {T}$atoms. For $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds the Fermi level ($\rm \bf {E_F}$) is located in a valley in the total density of states ($\rm \bf {DOS}$), while for $\rm \bf {PrPt_3B_2C}$ the $\rm \bf {E_F}$ is located in a crest. Our results predict the absence of superconductivity in $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds, while the enhancement of $\rm \bf {DOS}$ at the $\rm \bf {E_F}$ in $\rm \bf {PrPt_2B_2C}$ compound indicates the possibility of superconductivity. Moreover, the $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds indicate strong and similar type of hybridization while different and reduced hybridization in $\rm \bf {PrPt_2B_2C}$ compound is observed. Transport properties performed by our group confirms the existence of superconductivity in $\rm \bf {PrPt_2B_2C}$ while the high value of Sommerfeld constant ($\gamma$ $\approx$ 200300 $\rm mJ/molK^2$) in $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds might be connected by an enhancement of the hybridization observed here. [Preview Abstract] 

R1.00032: Bondorbital models for wurtzite semiconductors WanTsang Wang, Ikai Lo, ShiowFon Tsay, MingHong Gau, JihChen Chiang A simple theoretical method for calculating electronic band structures of wurtzite materials based on the bondorbital model is presented. This method can be used to study many problems such as band mixing and effects of external fields (electric field, magnetic field, and unaxial stress, etc.), since it can reproduce fairly accurate lowest conductionband and top three valenceband structures. This method is very similar to LCAO method; however, it is much simpler and requires less computational effort than LCAO method. [Preview Abstract] 

R1.00033: Electronic structure calculations based on the twobody reduced density matrix, semidefinite programming, and threeindex representability conditions Bastiaan J. Braams, Mituhiro Fukuda, Maho Nakata, Michael L. Overton, Jerome K. Percus, Makoto Yamashita, Zhengji Zhao For nonrelativistic electrons in an external potential the ground state energy depends only upon the twobody reduced density matrix (2RDM) and a lowerbound approximation may be obtained by minimizing the energy with respect to the 2RDM subject to some representability conditions. Work going back to the 1970s and the recent work [1] showed that by imposing the wellknown $P$, $Q$, and $G$ conditions an accuracy is obtained that compares favorably to HartreeFock. In our work [2] we impose additional ``threeindex'' representability conditions and demonstrate an accuracy that is fully competitive with CISD or CCSD(T) on the same model space for a variety of small molecules. The approximation has a welldefined solution  there are no local minima  and is size consistent. The poster will present further results and experience and will discuss remaining computational challenges. [1] Nakata, M.\ et al., J.\ Chem.\ Phys.\ 114 (2001) 82828292. [2] Zhao, Z.\ et al., J.\ Chem.\ Phys.\ 120 (2004) 20952104. [Preview Abstract] 

R1.00034: The Photon Impulse Equation Sergej Reissig By using of the Newton formula $F=\frac{dp}{dt}=\frac{d(mc)}{dt} $ (1) together with the Einstein formula $E=mc^2$ the following equation can be received : $F=\frac{d(mc)}{dt}=\frac{1}{c}\cdot \frac{d(mc^2)}{dt}=\frac{1}{c}\cdot \frac{dE}{dt}$ (2). In [1,2] was shown: ${dE} \mathord{\left/ {\vphantom {{dE} {dt}}} \right. \kern\nulldelimiterspace} {dt}=P=hf^2$ (3). The solution of the equation system (2,3) delivers the expression for the photon force:$F=\frac{1}{c}\cdot hf^2=\frac{hc^2}{c\lambda ^2}=\frac {hc}{\lambda ^2}=\frac{hf}{\lambda }$ (3). With Eq. (2) and (3) the following relationship can be presented:$\frac{d(mc)}{dt}=\frac{E} {\lambda }=mc\frac{c}{\lambda }$ (4). The Eq. (4) let us to derive the photon impulse equation finally: $\frac{dp}{p}=\frac{d(mc)}{mc}=f\cdot dt$ (5). [1] About the calculation of the photon power. S. Reissig, Bulletin of the APS, March Meeting 2004, Part I, Montreal, Vol. 49, No.1, p. 255 [2] The Photon Power and StefanBoltzmann Radiation Law. S. Reissig, Bulletin of the APS, March Meeting 2004, Part I, Montreal, Vol. 49, No.1, p. 255. [Preview Abstract] 

R1.00035: Einstein and the Electron Milo Wolff, Geoff Haselhurst Querying Einstein. In his later years, physicists queried Einstein about the plethora of particles found with highenergy accelerators. They wanted Einstein's thought on basic matter. Einstein, a careful thinker, seriously replied, ``I would just like to know what an electron is.'' He implied that the prosaic electron, was more important to science than billions spent on accelerators. Little attention was paid to his remark. But Einstein saw the electron as the leading player of the Universe, because most activity is energy transfers between electrons. At the time, no one understood the energy mechanism of the electron; Although electron forces can be calculated with rules of Physics 101, the rules did not always match Nature. The electron did not appear to be a discrete particle. Something was wrong and Einstein knew it. We follow a suggestion by Clifford and Schroedinger to reject the discrete electron and replace it with a Wave Structure of Matter. This has all the electron's experimental properties, including the origins of the natural laws, fulfilling Einstein's intuition. (www.SpaceAndMotion.com) [Preview Abstract] 

R1.00036: Single channel conductance of H$_2$ molecules Victor Manuel GarciaSuarez, Alexandre Reily Rocha, Steve Bailey, Colin Lambert, Stefano Sanvito, Jaime Ferrer We report a detailed theoretical study of the atomic arrangement and conduction channels of an $H_2$ molecule joining either Platinum or Palladium electrodes. We find that the bonding state of the molecule does not hybridize with the leads if the molecule forms a bridge, thereby providing a single conductance channel. On the contrary, both channels hybridize heavily, leading to high conductances, if the molecule lies perpendicular to the electrodes,. We propose that the occurrence of additional transitory peaks in conductance histograms of Pd electrodes are due to the dissolution of Hydrogen atoms in the neighborhood of the bridge, which form metastable states. [Preview Abstract] 

R1.00037: Multiscale Modeling of Functionalized SingleWall Carbon Nanotubes Soumya Patnaik, Xiaofeng Duan, Brahim Akdim, Ruth Pachter Funtionalization of carbon nanotubes is significant for many reasons. Along with enhancing the processability of the nanotubes which can aid in applications such as nanotube reinforced composites, covalent chemical functionalization provides a means for better control over their electronic and mechanical properties. Functionalization of singlewall carbon nanotubes (SWCNTs) has been observed to exhibit diameter selectivity and proposed as a method for SWCNT purification [1]. In the present work, we report a multiscale modeling approach, combining atomistic molecular dynamics (MD) and first principles density functional theory (DFT) methods, to study the effects of SWCNTs carboxy functionalization. The MD simulations provide important information regarding intertube interactions upon functionalization. This was used in subsequent DFT calculations for a correct prediction of resonant Raman modes shifts in SWCNT bundles. The MD simulations, electronic structure calculations, and predicted Raman shifts in comparison with experiment [1] will be discussed in detail. [1] Kuzmany, H., Kukovecz, A., Simon, F., Holzweber, M., Kramberger, Ch., and Pichler, T., \textit{Syn. Met}. 2004, 141, 113122. [Preview Abstract] 

R1.00038: Inferring the equation of evolution of a thinfilm superconductor Rotha Yu We infer the equation of evolution of a thinfilm superconductor that is known to obey an otherwise unspecified (2+1)dimensional timedependent complex GinzburgLandau equation, given measurements on the probability density of the governing complex field and gauge fields. The formalism is tested using simulated data. [Preview Abstract] 

R1.00039: About The Photon Physical Properties Sergej Reissig In [1] the formula for the determination of the photon force was received:$\left F \right=\frac{hc}{\lambda ^2}$ (1). The pressure of the photon can be calculated according to the following formula [1]: $P=F \mathord{\left/ {\vphantom {F A}} \right. \kern\nulldelimiterspace} A$ (2). In [2] the effective area of the photon was defined: $A=\pi \lambda ^2$ (3). By using the Eq. (1) together with Eq. (2) and (3) the following equation can be derived:$P=\frac{hc}{\pi \lambda ^4}$ or $P=const\cdot \lambda ^{4}=6.323052{\kern 1pt}\;10^{26}\cdot \lambda ^{4}$ (Pa) (4). The thermodynamic analysis has shown that the equation $P_h V_h =kT$ can be used by describing of the photon thermodynamic condition in such form $P_p V_p =hf$(5). The use of the Eq. (4) and (5) makes the calculation of the photon volume $V_p $ possible: $V_p ={hf} \mathord{\left/ {\vphantom {{hf} P}} \right. \kern\nulldelimiterspace} P_p =\pi \lambda ^3$ (6). The new equations (5,6) were proved with one theoretical procedure: ${{dE} \mathord{\left/ {\vphantom {{dE} {dt}}} \right. \kern\nulldelimiterspace} {dt}=d(PV)_p } \mathord{\left/ {\vphantom {{{dE} \mathord{\left/ {\vphantom {{dE} {dt}}} \right. \kern\nulldelimiterspace} {dt}=d(PV)_p } {dt}}} \right. \kern\nulldelimiterspace} {dt}=hf^2$ (7). Finally, it is possible to calculate the density of the light particle: $V\rho =m=h \mathord{\left/ {\vphantom {h {c\lambda }}} \right. \kern\nulldelimiterspace} {c\lambda }$ or $\rho =const\cdot \lambda ^{4}=0.703534\;10^{42}\cdot \lambda ^{4}$ [kg/m$^{3 }$] (8). With the Eq. (4) and (8) one other pressure equitation can be expressed: $P=\rho c^2$ (9). The multiplying the left and right sides of this formula on V by using the Eq. (5) delivers the famous, wellknown Einstein formula $E=mc^2$. \textbf{[1] }Determination of the Photon Force and Pressure. S. Reissig, The 35th Meeting of the DAMOP, May 2529, 2004, Tuscon, abstract {\#}D1.102\textbf{ [2}] The Photon Power and StefanBoltzmann Radiation Law. S. Reissig, Bulletin of the APS, March Meeting 2004, Part I, Montreal, Vol. 49, No.1, p. 255; http://efbr.org/de/publikationen/EFBR{\%}20Publikationen.htm [Preview Abstract] 

R1.00040: ARTIFICIALLY STRUCTED MATERIALS II 

R1.00041: A study on 1D photonic crystals composed of oxide multilayers Meidong Huang, Younghoon Hyun, Ryojin Kim, Youngpak Lee, Kiwon Kim Multilayers, consisting of oxide layers, have been designed for 1D photonic crystals. The optical transfer behavior at normal incidence was calculated in the visible range. The computed results show that the complete reflectance can be achieved when the structural repetition number is large enough. The more the number of periods is, the better control over the fine details of spectral reflectance profile is found. It is interesting that a defect mode can be obtained when the halfwavelengththick layer is sandwiched symmetrically by two quarterwavelengththick layers. More defect modes are observed when the sandwiched layer is magnetic. However, no defect mode is formed when the thickness of sandwiched layer is a quarter wavelength. The designed multilayers were also fabricated to confirm the predicted properties. [Preview Abstract] 

R1.00042: One Dimensional Photonic Crystals with Semiconducting Constituents: Photonic Bands Near The Polaritonic Gap Edges Jesus ManzanaresMartinez, Felipe RamosMendieta We have calculated the photonic band structure (PBS) and the optical properties of two periodic layered systems: air/LiTaO$_{3}$ and air/InSb. In our calculations the dielectric constant of the semiconductors takes into account the phononic contributions. Intrinsic electron and hole densities are also considered for the InSb. We have found that the PBS presents metallic behavior at frequencies just above the transverse phononic frequency and below the effective plasma frequency. Further the absorption mechanisms give rise to inflexion points in some bands  the curve of dispersion returns without reaching the Brillouin zone limit. An infinite concentration of nondispersive bands is found below the polaritonic gap when the absorption is neglected. However, with realistic absorption such infinite series of flat bands disappears, giving place to a finite number of dispersive bands. [Preview Abstract] 

R1.00043: Electromagnetic Field in One Dimensional Photonic Crystals by Using the Finite Difference Time Domain (FDTD) Method Marco A. LopezEsquer, Felipe RamosMendieta, Jesus ManzanaresMartinez In this work we present a simulation of the electromagnetic field in one Dimensional Photonic Crystal (1DPC) using the Finite Difference Time Domain (FDTD) Method. In first place, we present the time evolution of a monochromatic sinusoidal wave through a 1DPC of finite length. The behaviour of the field is governed by the Photonic Band Structure (PBS) of the infinite crystal. We describe the propagation at allowed and forbidden frequencies. For the allowed frequencies, we present the vibration modes at each one of the FabryPerot oscillation minimums. For the forbidden frequencies, we present a relation between the imaginary Bloch vector and the decay of the wave through the structure. In second place, we present how the group velocity changes the light propagation of a pulse inside the finite crystal, especially in the case when the central frequency is near to the band edge. Finally, we analyse the role of the absorption in both cases. [Preview Abstract] 

R1.00044: The large full band gaps for photonic crystals in two dimensions Han Kuei Fu, Yang Fang Chen, R. L. Chern, Chien. C. Chang The large full band gaps of twodimensional photonic crystals have been designed, fabricated, and characterized. The design of photonic crystals was based on the calculation using the inverse iteration with multigrid acceleration. The fabrication of the photonic crystals on silicon was realized by the processes of electronbeam lithography and inductively coupled plasma reactive ion etching. It is found that the hexagonal array of circular columns and rods have the optimal full photonic band gaps. In addition, a large extraction of light from our designed two dimensional photonic crystals was obtained when compared with that of the frequently used photonic crystals with triangular lattices. [Preview Abstract] 

R1.00045: Visualization of the light injection in one dimensional Photonic Crystals. Raul ArchuletaGarcia, Felipe RamosMendieta, Jesus ManzanaresMartinez In this work we present time variation simulations of the light injection in one dimension photonic crystals (1DPC). This phenomenon is due to the coupling of an incoming planewave to the discrete vibration modes in finite 1DPC. In order to present a live animation of the system we proceed in two stages. First, we present the discrete relation dispersion and then we choose the better combination of frequency and wavevector. Second, for this combination we reconstruct the field amplitudes in each one of the media. This phenomenon has been described in three previous works [13] for the case of a metaldielectricmetal system. In this work we present the simulation of this system and also the extension of the idea for the case of a multilayer system. The visualization of the electromagnetic field gives a better comprehension of the phenomena. [1]R. GarciaLlamas, J.A. GasparArmenta, F.RamosMendieta, R.F. Haglund, R. Ruiz. \textit{``Design, manufacturing and testing of planar optical waveguide devices'',}.), Proceedings of SPIE, vol. 4439, 2001, pp 8894. [2] F. Villa, T. LopezRios, L.E. Regalado, ``\textit{Electromagnetic modes in metalinsulatormetal structures''}, Phys. Rev. B 63 (2001) 165103. [3] A.S. RamirezDuverger, R. GarciaLlamas, ``\textit{Light scattering from a multimode waveguide of planar metalic walls''}, Optics Communications, (2003) [Preview Abstract] 

R1.00046: Electron charge decoherence due to electronphonon coupling in a semiconductor double quantum dot Vasilios Stavrou, Xuedong Hu We have studied single electron charge relaxation and dephasing rates in laterally coupled GaAs double quantum dot due to electronphonon interaction. We first calculate the single electron wavefunctions in the double dot using a basis formed by the FockDarwin states. For the electronphonon interaction we include both deformation potential and piezoelectric coupling. Our results show strong dependence of the relaxation and dephasing rates on interdot distance, confinement strength, and interdot bias. [Preview Abstract] 

R1.00047: ATOMIC, MOLECULAR & OPTICAL (AMO) PHYSICS 

R1.00048: Extensions of the BoseHubbard Model for BEC in a DoubleWell Potential David Ananikian, Thomas Bergeman To connect 1D theoretical results and experiments on Bose condensates trapped in a doublewell longitudinal potential in quasi1D waveguides, there are two possible effects to consider: a) the ``tightbinding'' approximation may not apply, and the wavefunctions in a well may vary with atom number due to atom atom repulsion; and b) the transverse confinement may not be tight enough to ensure a uniform transverse wavefunction factor. We have developed a series of successively more complete approaches: a) an ``exact'' 1D twomode model, based on symmetric and antisymmetric solutions of the GrossPitaevskii (GP) equation in 1D, exhibits twoparticle tunneling effects; b) a multimode model; c) numerical solutions of the 1D time dependent GP equation match the twomode results for small interactions; d) numerical calculations of the TDGP in 3D using splitoperator techniques take into account behavior in the transverse direction. Our results with d) are in good agreement with experimental observations by the Oberthaler group in Heidelberg. [Preview Abstract] 

R1.00049: Bosons among KronigPenney layers Miguel A. Solis, Mirta Rodriguez, Marcela Grether We describe the statistical behavior of an ideal boson gas among periodic plane layers which are simulated by an external KronigPenney potential in the $z$direction while bosons are allowed to be free in the other two directions. The critical temperature goes from the 3D ideal boson gas critical temperature to that of a quasi2D boson gas inside a slab of wide $a$, as $P = mV_0 ab/\hbar^2$ goes from zero to infinity. When we turn on a small repulsive (attractive) interaction between bosons, the critical temperature increases (decreases) compared to the ideal case with the same $P$ and $a$. We also calculate and discuss other thermodynamic properties such as the specific heat. [Preview Abstract] 

R1.00050: Condensateprofile asymmetry of a boson mixture in a diskshaped harmonic trap Hong Ma, Tao Pang A mixture of two types of hardsphere bosons in a diskshaped harmonic trap is studied through pathintegral quantum Monte Carlo simulation at low temperature. We find that the system can undergo a phase transition to break the spatial symmetry of the model Hamiltonian when some of the model parameters are varied. The nature of such a phase transition is analyzed through the particle distributions and angular correlation functions. The asymmetry has a strong dependence on the aspect ratio of the axial confinement along the $z$ direction and the radial confinement in the $xy$ plane, the ratio of the interaction ranges $a_{11}/a_{22}$, and the temperature. Furthermore, the total numbers of particles in the two species and significant difference in the external potentials can also affect the structures of the condensates. Comparisons are made between our calculations and the available meanfield results on similar models. Possible future experiments are suggested to verify our findings. [Preview Abstract] 

R1.00051: Critical Time and Length Scales and New Procedures for Performing ``Squeezed State Atom Interferometry,'' Using BEC's in Finite Optical Lattices Scott Chubb Kasevich has suggested\footnote{M. Kasevich, Compte Rendus, Serie IV, 2,, \#3 : 497507} that ``squeezed state interferometry,'' using Bose Einstein Condensates (BEC’s) in Optical Lattices, may be useful for developing new, potentially revolutionary procedures for measuring gravity, acceleration and$/$or values of $\hbar$$/m$$_a$$_t$$_o$$_m$. The essential physics associated with his argument involves being able to address and manipulate, many atoms, in a BEC, at many locations, simultaneously, coherently (using an Optical Lattice), beginning from a nonBEC, manybody Fock state (for example, initialized from a Mott insulating state). A variant of his idea includes an additional procedure in which the Optical Lattice is accelerated coherently for discrete intervals of time in such a way that the BEC effectively ``sees'' an Umklapp transition in the direction of gravity and then (using a rotated lattice) perpendicular to it. A complication, associated with the new procedure, involves identifying the effects of boundaries and limitations associated with the finiteness of the lattice. Using a generalization of band theory to finite lattices\footnote{Scott R Chubb, Bull of the APS, v 49,\#1, part 2, 549 (2004.)}, estimates of critical time and length scales, based on simulations of the propagation of representative wavepackets, are used to quantify the effects of these limiting factors. [Preview Abstract] 

R1.00052: Structure Determination of Small Metal Clusters by DensityFunctional Theory and Comparison with Experimental FarInfrared Spectra Andre Fielicke, Christian Ratsch, Joerg Behler, Matthias Scheffler, Gert von Helden, Gerard Meijer Small metal clusters or nanoparticles exhibit properties that are often quite different from those in the bulk phase. For example, small metal clusters have been shown to exhibit unusual magnetic properties. Small nanoparticles also play an increasingly important role in catalysis. Therefore, it is paramount to gain a better understanding of the atomic structure and properties of small metal clusters. The sizespecific farinfrared vibrational spectra for charged vanadium clusters as well as charged and neutral niobium clusters with sizes between 3 and 24 atoms have been measured using infrared multiple photon dissociation. Using DFT calculations, we calculated the ground state energy and vibrational spectra for a large number of stable and unstable geometries of such clusters. Comparison of the calculated vibrational spectra with those obtained in the experiment allows us to deduce the cluster size specific atomic structures. [Preview Abstract] 

R1.00053: Highly compact wavefuntions for Helike systems Frank E. Harris Wavefunctions which are compact, but still quite accurate, are extremely valuable as tools for gaining understanding of quantum systems. Here we study the ground electronic states of the threebody systems comprising the He isoelectronic series, using spatial wavefunctions that depend exponentially on all the interparticle distances, i.~e. built from a basis whose members are of the form $\phi_i=(1+{\sf P}_{12})\exp(\alpha_i r_1 \beta_i r_2 \gamma_i r_{12})$, where $r_1$ and $r_2$ are the electron nuclear distances, $r_{12}$ is the electronelectron separation, and ${\sf P}_{12}$ permutes the electron coordinates. When the nonlinear parameters $\alpha_i$, $\beta_i$, $\gamma_i$ are carefully optimized (a nontrivial task), this type of basis is found to be extraordinarily efficient; using as few as four basis functions, it is found that nonrelativistic energies are reproduced to within 38 microhartrees of the exact values, an error far less than for compact wavefunctions previously proposed by others. Other properties, including those totally dependent upon the electron correlation, are also well represented.\\ Supported by U.S. National Science Foundation Grant PHY0303412. [Preview Abstract] 

R1.00054: Nondipole effects and ``drag'' of photoelectrons in the calcium vapor Valeriy Dolmatov, Daniel Bailey Nondipole photoelectron angular distributions from atoms, molecules, and solids, used to be ignored when interpreting their photoelectron spectra, have become an ad hoc topic of intensive research in recent years. To the surprise of many, on numerous occasions, they have been found to be comparable to those produced in dipole photoionization. Also, nondipole effects are known to result in ``dragging'' the photoelectrons along or against the direction of passing photons. This leads to the appearance of electric currents (``drag'' currents) in gases. In this work, we demonstrate, firstly, that nondipole photoelectron angular distributions are extremely strong in 3p photoionization of Ca, owing to a discovered giant quadrupole 3s3d resonance in this atom. Secondly, we show that, as a consequence, the drag current appearing in the calcium vapor, is resonantly increased by several factors in magnitude, changes direction twice within the resonant photon energy region, and is quite measurable. The drag current would be a nice novel subject for advanced experimental studies. We strongly urge them. [Preview Abstract] 

R1.00055: Mean Excitation Energy for the Stopping Power of Silicon from OscillatorStrength Spectra Mitio Inokuti, William Karstens, E. Shiles, David Y. Smith The mean excitation energy, $I$, is the sole nontrivial property of matter appearing in Bethe's expression for the stopping power for a charged particle at high speed. When the dipole oscillatorstrength spectrum, d$f$/d$E$, is fully known as a function of excitation energy, $E$, the $I$ value may be evaluated from ln($I)=\smallint $ ln($E)$ (d$f$/d$E)$ d$E$ / $\smallint $ (d$f$/d$E)$ d$E$. Following up work on metallic aluminum, we are analyzing experimental data for the dielectric response of crystalline silicon using KramersKronig dispersion relations and sum rules. The experimental data include absorption, refraction, reflection, and EELS. For silicon, the best set of data in our current judgment gives $I$ = 163.5 $\pm $ 2 eV, where the uncertainty arises from using different but apparently equally reliable data and from numerical procedures. Our result is appreciably lower than the standard value, 173 $\pm $ 3 eV. It is noteworthy that our result for silicon is remarkably close to that for aluminum, both in the $I$ value and in the contributions to it from each electron shell (when scaled for electron occupation and shelledge energy). [Preview Abstract] 

R1.00056: Atonic Mechanics Calculations of He II Lines of R. L. Kelly Alfred Phillips, Jr. We have calculated the energy levels for the many spectral lines of He II for the unpublished data of R. L. Kelly. The 243 lines of data are given on the \underline {NIST Atomic Database Levels Data} web page with the proviso ``not evaluated by NIST.'' The data and calculations usually agree exactly. Discrepancies between measurements and calculations are found only when the electron is very close to the nucleus. The calculations were made using Atonic mechanics which provides of doing atomic mechanics without recourse to wave notions. [Preview Abstract] 

R1.00057: ReducedDensityMatrix Approach for Coherent Linear and Nonlinear Electromagnetic Interactions Verne Jacobs Reduceddensitymatrix descriptions are developed for linear and nonlinear electromagnetic interactions in quantized electronic systems, including atomic systems and semiconductors materials (bulk solids and heterostructures). Environmental decoherence and relaxation processes are treated on a formally equal footing with coherent electronelectron and electromagnetic interactions. Frequencydomain (resolventoperator) and timedomain (equationofmotion) formulations are selfconsistently developed. Compact Liouvillespace operator expressions are derived for the linear and arbitraryorder nonlinear electromagneticresponse tensors, allowing for coherent initial electronic excitations and for the full tetradicmatrix form of the Liouvillespace selfenergy operator representing the environmental interactions. [Preview Abstract] 

R1.00058: Formation of Ultracold GroundState RbCs via Photoassociated 1$^{1}\Pi$ State H. Wang, G. Iyanu Two electronic states, 1$^{1}\Pi$ and 2$^{1}\Sigma^{+}$, of the Rb(5s) + Cs(6p) atomic asymptote can be used to directly populate the RbCs ground state X$^{1}\Sigma^{+}$ at short range following heteronuclear photoassociation of lasercooled Rb and Cs atoms. Our FranckCondon factor calculation shows that the 1$^{1}\Pi$ state (dissociating to the Rb(5s) + Cs(6p$_{3/2}$) asymptote) is more favorable than the 2$^{1}\Sigma^{+}$ state (dissociating to the Rb(5s) + Cs(6p$_{1/2}$) atomic limit) for forming ultracold groundstate RbCs in low vibrational levels (v $<$ 20), which can be further efficiently transferred to the v = 0, J = 0 lowest quantum state of the molecule through a simple onephoton optical pumping process. Experimentally we have observed ultracold RbCs molecules in a RbCs dual MOT by twophoton ionization and timeofflight mass spectroscopy. Efforts are underway on heteronuclear photoassociation to the 1$^{1}\Pi$ state ($\Omega$ = 1 state at long range) and formation of ultracold RbCs in the singlet ground X$^{1}\Sigma^{+}$ state. In this paper we present our FranckCondon calculation on the transition scheme of using photoassociated 1$^{1}\Pi$ rovibrational levels to make ground state RbCs and report our experimental results and progress in heteronuclear photoassociation, detection and trapping of ultracold RbCs molecules. This work was supported under The Aerospace Corporations's Independent Research and Development Program. [Preview Abstract] 

R1.00059: Optical tuning of the scattering length of cold alkaline earth atoms E. Tiesinga, R. Ciurylo, P.S. Julienne It is possible to tune the scattering length for the collision of ultracold $^{1}S_{0}$ ground state alkalineearth atoms with a laser far detuned from optical Feshbach resonance with an excited molecular level near the frequency of the atomic intercombination $^{1}S_{0}$$^{3}P_{1}$ transition. Simple resonant scattering theory, illustrated by the example of $^{40}$Ca, allows an estimate of the magnitude of the effect. Unlike alkali atom species, large changes of the scattering length are possible while atom loss remains small, because of the very narrow line width of the molecular photoassociation transition. This raises prospects for control of atomic interactions for a system without magnetically tunable Feshbach resonance levels. [Preview Abstract] 

R1.00060: Resonance Enhanced Weak Values in Attenuated Total Internal Reflection Xiaobo Yin, Lambertus Hesselink, Henry Chin, David A. B. Miller, Zhaowei Liu, Nicholas Fang, Xiang Zhang We explain the first order nonspecular optical effects in reflection through a quantum mechanical approach based on weak measurements with postselection. A generalized formalism of the weak values in a reflection experiment is derived and both real and imaginary parts are associated with physically observable quantities, the GoosH\"{a}nchen spatial shift, angular deviation, the Wigner delay time and the central carrier frequency shift. To verify the predicted effects, the weak values are amplified through an attenuated resonant device and examined in three optical experiments where three quantities out of four are examined with polarization modulation technique and an ultrafast laser. The results are in good agreement with theoretical prediction by weak measurement. [Preview Abstract] 

R1.00061: Femtosecond Spectroscopy of ElectronLattice Coupling in LuMnO$_{3}$ Shitao Lou, Frank M. Zimmermann, Robert A. Bartynski, N. Hur, S.W. Cheong Hexagonal manganite LuMnO$_{3}$ is a ferroelectric (T$_{c }\approx $ 900 K) and strongly frustrated antiferromagnetic (T$_{N} \approx $ 90 K) crystal. Strong coupling between lattice, electronic, and magnetic degrees of freedom make it a promissing electronic material. We have used femtosecond pumpprobe spectroscopy to observe the interaction of electron excitation and lattice vibration in real time. Optical excitation at a sharp absorption peak at 800 nm corresponding to a Mn $d_{(x^2y^2),(xy)} \to d_{(3z^2r^2)} $transition served as the primary excitation step. Reflectivity changes as a function of delay time reveal electronic relaxation and coherent oscillations of several optical phonon modes. Electron and phonon excitation and relaxation dynamics were studied using different polarization geometries and symmetry analysis. The interaction mechanisms of photons, electrons, and coherent phonons are discussed. [Preview Abstract] 

R1.00062: Heavy atom tunneling in chemical reactions at ultracold temperatures P.F. Weck, N. Balakrishnan Over the last few years, experimental methods such as the buffergas cooling or the photoassociation techniques have succeeded in producing gases of cold and ultracold molecules. These remarkable technical achievements open new perspectives in the study of intermolecular interactions and by the same token raise new concerns about rovibrational relaxation and chemical reactivity of molecules in the ultracold regime. In the present work, we report quantum scattering calculations of atomdiatom reactions at cold and ultracold temperatures. Specifically, we investigate the H + LiF and Li + HF collisions at ultralow energies for which the reactions proceed by quantum tunneling of the exchanged atom through a barrier along the reaction path. Particular attention is paid to the resonance structure originating from quasibound states of the Li...FH and H...LiF van der Waals complexes. [Preview Abstract] 

R1.00064: QUANTUM FLUIDS AND SOLIDS 

R1.00065: Quantum Decay in Coupled Bosonic Systems George Cragg, Arthur Kerman For species having negative swave scattering lengths, atomic condensation is impossible above some critical number of atoms. Using a Feshbach resonance to create a coupling to a molecular state of the system enables the effective scattering length, $a$, to be tuned to positive values, where it is believed to then result in stability. In spite of being in the positive scattering length regime, we have found that a collapsing ground state remains. In addition, we obtain an excited state which exhibits the expected lowdensity dependencies, but where the imaginary part of the chemical potential quantifies the time of decay into collective phonon excitations of the collapsing ground state. Consequently, this leads to a unique decay rate dependency on both the scattering length and the density, $\sim a^{5/2}\rho^{3/2}$, which can be experimentally tested. Using our predicted rate, there is good agreement with the overall lifetime observed in $^{85}$Rb. [Preview Abstract] 

R1.00066: Nuclear spin relaxation times in hydrogenhelium and methanehelium slush at 4 MHz using pulsed NMR J.A. Hamida, N.S. Sullivan We compare the nuclear spinlattice and nuclear spinspin relaxation times observed for small grains of hydrogen suspended in liquid helium (hydrogenhelium ``slush'') with that of methanehelium ``slush.'' The transport properties of these ``slush'' materials are critical to NASA's goal of realizing atomic propellant designs for future spacecraft. Atoms of active propellants are stored cryogenically in a host matrix such as hydrogen (H$_{2})$ or methane (CH$_{4})$ to prevent recombination while liquid helium is ideal for holding the host matrix and for easy transportation. The host matrix must therefore be stable in liquid helium. We find that for hydrogen ``slush,'' NMR rate is consistent with scattering at grain boundaries due to the large electric quadrupole moment of hydrogen; on the other hand the ``slush'' rate for methane is consistent with internal diffusion as opposed to surface scattering. We conclude that for atomic propellants, methane is a better host than hydrogen because grains of methane are better isolated from the helium bath. [Preview Abstract] 

R1.00067: Development of an ultralow Helium Loss HiTc Magnet Lead System Yuko Shiroyanagi, Thomas Gramila Approaches for HiTc superconducting magnet leads are available for high current applications and/or in combination with active cryocoolers. Incorporation of these leads into a typical research cryostat, however, faces difficulties related to their critical temperature, and perhaps surprisingly, their intrinsically low thermal conductivity. We have developed an approach for the use of HiTc leads in such cryostats which utilize commercially available tape to carry currents of a hundred amperes, while maintaining very low liquid helium boiloff rates. This design relies on a parallel thermal path to tailor the temperature profile of the superconducting tape and is incorporated into our previously developed lead system, which couples the heat of the magnet leads to the exiting helium gas through the cryostat baffles. Computer modeling of the leadcryostat system, including all relevant thermal paths, enables us to optimize the lead design, resulting in a net increase in helium boiloff for the incorporation of the leads into a cryostat of approximately one half liter per day without current, and of one liter per day when carrying a full hundred amperes. The design and implementation of the mechanical system necessary for this ultralow helium loss magnet lead system will be presented. [Preview Abstract] 

R1.00068: COMPLEX STRUCTURED MATERIALS 

R1.00069: Confinement of Equilibrium Polymers Edward Feng, Glenn Fredrickson We consider supramolecular polymer systems in which reversible intermolecular bonding affects the thermodynamics of the system. While we have formulated models for a number of such systems, this presentation focuses on equilibrium polymers in which monomers can reversibly link together to form linear polymers. This serves as a model for giant micelles of surfactant molecules that can break and recombine at any point along the cylindrical micelle. While equilibrium polymers in bulk environments have been studied, we investigate their behavior in confined environments such as between two parallel plates. Our model features a continuous distribution of polymer lengths and assumes a favorable energy decrease when two monomers form a bond. We are interested in how confinement affects the density profile and the polymer length distribution, and we calculate these properties analytically using the ground state dominance approximation and computationally employing selfconsistent field theory. [Preview Abstract] 

R1.00070: Mechanical Properties of Sheared Ternary Mixtures Rui Travasso, Gavin Buxton, Olga Kuksenok, Kevin Good, Anna Balazs Using two different simulation techniques, we study structural evolution and mechanical properties in two dimensional ternary mixtures. In particular, we determine the effect of shear on the Young's modulus of the system. We use the mesoscale Lattice Boltzmann technique to simulate the coarsening of ternary mixtures, with and without shear, for different mixture compositions inside the spinodal region. The shear flow strongly affects the system's evolution and leads to domain elongation along the shear direction. These morphologies serve as input to the Lattice Spring Model to study macroscale mechanical properties of the composites. We calculate the Young's modulus as function of the composition of the ternary mixture in both sheared and unsheared cases. We show that the presence of shear significantly enhances (up to 40%) the Young's modulus when the tensile force is applied in the shear direction. In addition, shearing prevents the Young's modulus of the system from decreasing while coarsening. [Preview Abstract] 

R1.00071: Lattice Optimization with Adaptive Tempering Simulations Xiao Dong, Estela BlaistenBarojas An Adaptive Tempering optimization based on multicanonical Monte Carlo is proposed to optimize the structure of the solid crystal obtained at low temperatures in an annealing process. The parameters that link the subcanonical ensembles are adapted progressively during the simulation. Solidification from a liquid system can be achieved through this method fairly fast. Tests of the method were done on LennardJones (LJ) liquid systems of various computational box sizes with periodic boundary conditions. Quenching from high temperature, the systems crystallized with few defects in a single pass of the tempering. The only observed defects were one or two stacking faults. The method was additionally tested on LJ clusters, for which the global minimum structure was obtained at the end of the quench. [Preview Abstract] 

R1.00072: Plasmon excitations in multicoaxial cables Bahram DjafariRouhani, Manvir S. Kushwaha We report on the theoretical investigation of plasmon excitations in multicoaxial cables (MCC) within the framework of a Greenfunction theory in the absence of any applied magnetic field. As an application, we present illustrative examples on the dispersion characteristics of the confined and extended plasmons in the perfect as well as (geometrically) imperfect system. The computed local density of states (LDOS) enables us to specify the spatial positions of both kinds of modes existing in the system. The elegance of the formalism lies in the fact that it does not require the matching of the messy boundary conditions and in its simplicity and the compact form of the desired results. Such quasione dimensional systems are proving to be the backbone of the emerging optoelectronics and telecommunications systems. [Preview Abstract] 

R1.00073: Mechanical Properties of Viral Capsids Roya Zandi, David Reguera Viral genomes, whether they involve RNA or DNA molecules, are invariably protected by a rigid, singleproteinthick, shell referred to as ``capsid.'' Viral capsids are known to tolerate wide ranges of pH and salt conditions and to withstand internal pressures as high as 100 atms. We study the mechanical properties of viral capsids, calling explicit attention to the inhomogeneity of the shells that is inherent in their being discrete/polyhedral rather than continuous/spherical. We analyze the distribution of stress in these capsids due to isotropic internal pressure (arising, for instance, from genome confinement and/or osmotic activity), and compare the results with appropriate generalizations of classical elasticity theory. We also examine the competing mechanisms for viral shell failure, e.g., inplane crack formation vs radial bursting. The biological consequences of the special stabilities and stress distributions of viral capsids are also discussed. [Preview Abstract] 

R1.00074: Raman and Electrical Characterization of Dielectrophoretically Deposited Single Wall Carbon Nanotubes Pehr Pehrsson, Lars Ericson We examine the directed assembly and electronic type sorting of single wall carbon nanotubes by dielectrophoresis and electrophoresis. We compare the deposition process for raw (unprocessed), and processed nanotubes from several surfactants. In addition, nanotubes were functionalized with biomolecules and other species of interest for sensor applications. Deposition is conducted with various electrode configurations, spacing, metals, and ac and dc electric field profiles. The deposited material is analyzed by microRaman scattering spectroscopy using 4 wavelength sources and electrically characterized by IV and gatevoltage measurements. [Preview Abstract] 

R1.00075: Theoretical Study of SingleWall Carbon Nanotubes Functionalization: Reaction Mechanisms and Raman Characterization Xiaofeng Duan, Brahim Akdim, Ruth Pachter Functionalization of singlewall carbon nanotubes (SWCNTs) may enable separation by chirality or diameter. For example, electronic structure tailoring by chemical functionalization was recently demonstrated using watersoluble diazonium salts (Strano et al., Science, 2003). In our work, applying density functional theory calculations, we examined the reaction pathways for C(5,5) and C(10,0) SWCNTs, functionalized with a 4chlorophenyl group. Our results show that a chargetransfercomplex is involved in the functionalization, providing an understanding of experimental observations. At the same time, to avoid misconceptions, it is important to validate theoretical models used in studying functionalization, for example, by comparison with experimental Raman spectra shifts. As the upshift of the Raman breathing modes in carboxySWCNTs was well characterized, we investigated changes in the electronic structures, as well as the effects of intertube interactions in SWCNT bundles for this system. The calculated interaction energies and charge transfer are consistent with the small experimental upshift. [Preview Abstract] 

R1.00076: Facile Growth of Suspended SWNTs by Wet Catalyst Method G.H. Jeong, A. Yamazaki, D. Takagi, M. Okuda, S. Suzuki, H. Yoshimura, Y. Kobayashi, Y. Homma Nanosized wet catalysts have recently employed for the singlewalled carbon nanotubes (SWNTs) growth with a uniform diameter, which is a key factor governing electronic properties of the SWNTs. Suspended SWNTs are useful for clarification of the physical/optical properties due to their interactionfree feature between substrate. For this reason, we tried to grow the diametercontrolled suspended SWNTs using pillar substrates and catalyticmetal containing organic molecules, which have refined catalyst size. Ferritin consisting of protein shell and encaging iron particles in its inner space and Cofilled apoferritin are utilized as a wet catalyst. By controlled experiments, SWNTs are successfully synthesized not only on flat substrates but also on Sisubstrates with nanopillars. Low concentration of the ferritin gives the narrow diameter distribution of the SWNTs, which is confirmed by Raman spectroscopy. In addition, suspended SWNTs with narrow tubediameter ranges are for the first time achieved using Cofilled aopferritins. [Preview Abstract] 

R1.00077: Electronic Deexcitations in Semiconducting Carbon Nanotubes ChihWei Chiu, J.H. Ho, C.P. Chang, R.B. Chen, F.L. Shyu, M.F. Lin The excited conduction electrons in semiconducting carbon nanotubes can effectively decay by the electronelectron Coulomb interactions. The main deexcitation mechanisms are the intraband excitations, but not the interband excitations. The decay rates strongly depend on the wavevector, the energy subbands, the temperature, and the nanotube radius. The calculated results could essentially explain the experimental measurements from the timeresolved photoemission spectroscopy. [Preview Abstract] 

R1.00078: Magnetization of Finite Carbon Nanotubes R.B. Chen, C.P. Chang, J.S. Hwang, F.L. Shyu, M.F. Lin Magnetoelectronic properties of finite carbon nanotubes (CN's) are studied for any field direction. Energy gap and agnetization are strongly affected by the nanotube geometries (length, radius; boundary structure), the magnitude and the direction of the magnetic field, the Zeeman effect, and the temperature. Geometric structures determine electronic structures and magnetic properties, which, thus, leads to three types of energy gaps and induced magnetic fields. The critical angle, which corresponds to the change of magnetism, exists in armchair CN's, but not in zigzag CN's. It also depends on the length and the radius. Finite CN's are very different from infinite CN's in the strength of magnetic response and the critical angle. The Zeeman splitting could induce the conductor metal transition, the drastic change in magnetization, and the gigantic paramagnetic response for all zigzag CN's. The predicted results are observable even at room temperature. [Preview Abstract] 

R1.00079: Improved Purification and Dissolution Properties of Carbon Nanotubes by Irradiation of Accelerated Particles. Ebrahim Najafi, Chongoh Lee, Kwanwoo Shin Carbon nanotubes (CNTs) have recently attracted much interest for their exceptional chemical and physical properties and unique aspect ratio. Yet, CNTs applications have been somewhat limited due to their retained impurities and limited solubility in most organic solvents. In this work, we study the feasibility of using accelerated particles (electrons and protons) to covalently modify CNT surface. Results show that accelerated proton radiation with a energy of 10 MeV, both in an ambient atmospheric condition, can generate oxygenrich functional groups, e.g. carboxylic acid and phenol, on CNTs surfaces and significantly improve their solubility without any significant surface damage. On the other hand, accelerated electron beam induced effective removal of SP$^{3}$ carbon bonding, resulting that physical welding of crossed carbon nanotubes. This work is supported by the Proton Accelerator (No. M202AK01002104A110102110) and Accelerated Electron User Program from the Nuclear R{\&}D Program. [Preview Abstract] 

R1.00080: Stabilizing Interactions in SWNT  Polypeptide Nanocomposites Kristopher Wise, Cheol Park, Peter Lillehei, Emilie Siochi, Joycelyn Harrison This contribution describes the computational component of a combined experimental and modeling study of nanocomposites consisting of single wall carbon nanotubes (SWNTs) dispersed in synthetic polypeptides. Our experimental results show that these composites possess an attractive suite of mechanical properties including increased modulus, strength, and elongation at break. In addition, the composites exhibit high, isotropic electrical conductivity and improved dielectric properties. Molecular dynamics simulations reveals that a number of stabilizing interactions are operative spanning several length scales. At the atomic level van der Waals bonding dominates. At larger length scales electrostatic interactions between antiparallel aligned $\alpha $ helical peptides promote the formation of bundles containing SWNTs in the centers. [Preview Abstract] 

R1.00081: $^{13}$C NMR Study of SingleWalled Carbon Nanotubes Moohee Lee, Kyuhong Lee, B. J. Mean, JaeKap Jung, KwonSang Ryu We have performed $^{13}$C nuclear magnetic resonance (NMR) measurements on singlewalled carbon nanotubes. Spectrum, shift,linewidth, and $T_1$ have been measured as a function of temperature from 4 K to 200 K under the magnetic field of 4.7 T. Spectrum shows a narrow lineshape for the $^{13}$C nucleus. Shift is very small and shows no significant change in the whole temperature range. The linewidth becomes broader with decreasing temperature from 13 kHz at 200 K to 21 kHz at 4.6 K. The spinlattice relaxation recovery is found to exhibit three types of relaxation channels; the fastest rate comes from magnetic impurities on the surface and the other two are due to metallic and non metallic parts of the nanotubes. [Preview Abstract] 

R1.00082: TimeDependent DensityFunctional Calculations of Photoabsorption Spectra of Carbon Nanostructures Tomoyuki Noguchi, Masaaki Araidai, Kazuyuki Watanabe Optical properties of nanoscale structures have attracted much attention experimentally and theoretically. It is not appropriate to apply the conventional densityfunctional theory (DFT) to investigation of the optical properties, because the excited states, which are not adequately represented by the DFT, play essential roles in these phenomena. To go beyond the DFT, we adopt timedependent DFT (TDDFT) calculations with the linear response theory, which is a powerful computational tool for calculating the excited states of nanostructures properly. In this study, we report the results of excitation energies and photoabsorption spectra in aromatic molecules, such as naphthalene and anthracene. A high spectral intensity in a low frequency region occurs in the spectra for these molecules. This characteristic spectrum is shifted to lower energy with increasing molecular size. We also discuss the details of the electronic excitations utilizing the TDDFT calculations in a realtime scheme. [Preview Abstract] 

R1.00083: Field Emission Mechanisms of Covalently Bonded Nanostructures Masaaki Araidai, Kazuyuki Watanabe Carbon materials have been found in various forms depending on the different covalent bondings, and intensively studied in anticipation of their application to new nanometerscale devices. Among the various applications of these covalently bonded nanostructures, electron field emitters made from carbon materials show significant promise for electronic devices, because they can maintain stable forms under extremely high fieldemission (FE) current densities owing to tight covalent bonds. In this study, FE mechanisms and the electronicstates origin of covalently bonded nanostructures are microscopically investigated by firstprinciples calculations based on timedependent densityfunctional theory. First, we investigate the FE of silicon clusters and extract a theoretical basis for understanding covalently bonded field emitters. Second, calculations of the FE of diamond C(100) surfaces are carried out and effects of hydrogen terminations and hydrogen defects in the subsurface on the FE are discussed by using electronic band structures. Finally, we address the effects of the electricfield direction on the FE characteristics of graphenes and graphitic ribbons. Central results in our study are that not only evaluation of work functions but also knowledge of local electronic properties, the $\sigma$ or $\pi$bonding states, are prerequisite for understanding the microscopic mechanisms of FE properties of covalently bonded nanostructures. [Preview Abstract] 

R1.00084: Large Scale Production of Carbon Single Walled Nanotubes by PlasmaChemical Recondensation Method Elena Korobko, Edward Dobrinsky, Stanislav Malashin, Anatoli Kuznetsov In order to exploit the unique properties of carbon single walled nanotubes (SWNTs) it is necessary to produce kilogram to ton quantities at reasonable prices, with controllable key parameters. Many groups have investigated gasphase continuousflow production of carbon SWNTs. Here we present the new plasmachemical technology of carbon SWNTs production, in which metal catalyst particles of iron were injected into an arc at a rate up to 5g/min through an opening in the electrode with the flow of Ar carrier gas. Further, the vaporized metal and the hydrocarbon gas mixed in the condensation chamber producing carbon soot. Characterization of produced carbon soot by electron microscopy also dependence of carbon SWNTs yield on synthesis parameters is presented. [Preview Abstract] 

R1.00085: Liquefaction of Catalyst Nanoparticles during Carbon SingleWalled Nanotubes Growth Elena Mora, Arthur Epstein, Toshio Tokune, Avetik Harutyunyan Despite the discovery of carbon single walled nanotubes (SWNTs) over a decade ago, the growth mechanism is still not fully understood. The question of whether the catalyst remains solid or not during the growth is still the subject of intense research. In the study reported here, two groups of catalysts with spherical and disk shape cobalt nanoparticles were used to grow SWNTs by chemical vapor deposition. The Raman spectra of the carbon deposits confirmed the formation of SWNTs. Additionally, electron microscopy images revealed that the disk shaped particles with diameter less than 20 nm were transformed into spheres during the synthesis. This implies that SWNTs were formed on the liquefied metal nanoparticles. However, calorimetric studies conducted on the pristine catalyst showed that the synthesis temperature was lower than the melting point of the catalyst nanoparticles. According to the cobaltcarbon binary phase diagram, the saturation of the metal with carbon atoms causes a decrease in the melting point. Based upon our results, we believe that SWNTs grow on the liquefied nanoparticles and that the liquefaction is caused by the diffusion of carbon atoms in the nanoparticles. [Preview Abstract] 

R1.00086: Field Enhanced Thermionic Electron Emission From a New Oxide Coated Carbon Nanotube Cathode Feng Jin, Christopher Day We will report high field enhanced thermionic electron emission from a new type of oxide coated carbon nanotube cathode. This cathode consists of a metal substrate with carbon nanotubes grown on top of its surface by plasma enhanced CVD technique. The carbon nanotubes are further coated with thermionic emission materials (BaO/SrO/CaO). Oxides are coated on carbon nanotubes by magnetron sputter deposition and spin coating techniques. The emission current density from this cathode is at least an order of magnitude higher than conventional thermionic cathode coated with same emission materials and operated at same temperature. This strong emission current is attributed to the field enhancement effect. Field enhancement effect is usually negligible for conventional thermionic cathodes. However, in this case significant field enhancement thermionic emission is induced by sharp carbon nanotubes tips. We will present comparison results on electron emission for three different cathodes: 1) oxide coated carbon nanotube cathode, 2) conventional oxide cathode, and 3) carbon nanotube cathode. [Preview Abstract] 

R1.00087: Adsorption on Carbon Nanotubes: A Transfer Matrix Method Alain Phares, David Grumbine, Jr., Francis Wunderlich The transfer matrix providing the thermodynamic properties of adsorption on nanotubes is recursively constructed and generalized to include the study of adsorption on nanotubes twisted to any order and of arbitrary diameter. Results are presented for hollow adsorption on carbon nanotubes. [Preview Abstract] 

R1.00088: Conductance of single walled carbon nanotubes by induced defects with ion irradiation Cristina GomezNavarro In this work we report direct evidences of the influence of artificially induced defects, on the electronic transport of single walled carbon nanotubes. Defects are induced by Ar$^{+}$ ionic bombardment. Consecutive ion irradiation doses are applied to nanotubes producing an uniform density of defects. After each dose the electrical characteristics of the same carbon nanotube are measured by using a conductive atomic force microscopy. Using this method we are able to measure the resistance vs. Length characteristic of the nanotube after each known dose of Ar$^{+}$ ions. The results are fitted to R(L)= R$_{C}$+R$_{0}$/2$\cdot $exp(L/ (L$_{0})_{total })$.where the localization length due to induced defect is 1/(L$_{0})_{total}$= 1/ (L$_{0})_{ini}$ + 1/ (L$_{0})_{def}$ . The data present a decrease of (L$_{0})_{def }$with increasing doses. [Preview Abstract] 

R1.00089: Calculation of Phonon Dispersion and Thermal Conductivity in Carbon Nanotubes Mayank Varshney, Vladimir A. Fonoberov, Alexander A. Balandin Many potential applications of carbon nanotubes in nanoelectronic circuits rely on effective removing of excess heat from the device active area. Heat in carbon nanotubes is mostly carried by acoustic phonons. In this work we have calculated phonon dispersion in carbon nanotubes using atomistic approach. The phonon dispersion was then used to calculate phonon density of states, heat capacitance and thermal conductivity. The thermal conductivity has been determined using the modified Callaway  Klemens approach, which accounts for the lowdimensional size effects [1]. The results of our calculations are compared with the experimental Raman spectroscopic study of carbon nanotubes and reported values of the thermal conductivity. The authors acknowledge the support of MARCO and its Functional Engineered Nano Architectonics (FENA) Focus Center. [1] A.A. Balandin, Thermal Conductivity of Semiconductor Nanostructures, in Encyclopedia of Nanoscience and Nanotechnology (ASP, Los Angeles, 2004) p. 425. [Preview Abstract] 

R1.00090: Characterization of Doped NanoWires with Scanning Tunneling Spectroscopy Fredy Zypman STM in spectroscopic mode, has proven to be a useful technique to extract global and local densities of states (DOS and LDOS) of bulk samples and their surfaces. Most theoretical efforts have concentrated on developing algorithms to convert IV curves into DOS or LDOS. However, a full theoretical description of such program, encompassing any sample, has not been developed yet. Recently, it has been possible to create metallic chains up to sevenatom long. With this in mind, we have developed a new theoretical solution to the problem of mapping Scanning Tunneling Microscopy currentvoltage curves into DOSEnergy curves. Our model is based on a selfconsistent solution to the quantum problem of electrons in the presence of an array of atomic clusters. The problem, being simpler than its three dimensional counterparts is solved exactly for DOS and for the currentvoltage curves. The main results are that the currentvoltage peaks at the position of the energies of the electron in the chain, and when an impurity is present in the chain, its position can be extracted from the value of a universal curve. A universal curve allows the measurement of the position of the impurity from experimentally available data, that is, the peaks of the IV curve. Work supported by Research Corporation through Grant Number CC5786 [Preview Abstract] 

R1.00091: A FirstPrinciples Study of Lithium Hydride Clusters Vladimir Bubulac, Sudha Srinivas, Julius Jellinek Structural and electronic properties of lithium hydride (Li$_{n}$H$_{m})$ clusters in the size range n=19 and m $\le $ n are studied using firstprinciples computations. The geometric forms and their electronic characteristics are obtained within a gradientcorrected density functional framework. The results are analyzed as a function of cluster size and composition. In particular, we follow the evolution of the properties as the composition changes from metalrich (m $<$ n) to stoichiometric (m=n). A comparison with the available experimental data is presented. Work supported by a PRIF Grant from Central Michigan University (SS) and the Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, USDOE under contract No. W31109ENG38 (JJ). [Preview Abstract] 

R1.00092: Lowtemperature thermal conductance in nanostructures Naoaki Kondo, Takahiro Yamamoto, Kazuaki Mii, Kazuyuki Watanabe Controlling thermal transport as well as electronic transport is a key issue for modelling nanosized electrical devices. In contrast to a number of studies on the electronic transport properties at room temperature, only a few works have been done about lowtemperature (low$T$) properties of thermal transport thus far. We study low$T$ thermal transport in onedimensional (1D) nanostructures, such as carbon nanotubes, graphitic ribbons, and metallic nanowires, by using Landauer formula of heat transport. Three major findings in this study are the following. (1)Thermal conductances in the present nanostructures are quantized and have the form of $n\times\pi^2k_B^2T/3h$ at low$T$, where $n$ is the number of excited phonon mode depending on the structural geometry. (2) The temperature range where the quantization is observable is unexpectedly large for metallic nanowires. (3)Interestingly, phonon modes highly localized at open edges contribute to the quantized thermal conductance in graphitic ribbons. [Preview Abstract] 

R1.00093: Nanopatterned circuits in silicon: towards gain and logic Bonnie A. Sheriff, J.E. Green, E. JohnstonHalperin, R.A. Beckman, J.R. Heath High density arrays of doped silicon nanowires (NWs) have been demonstrated using the SNAP technique. This technology enables the fabrication of nanoscale memory devices, field effect transistor (FET) arrays, and biological and chemical sensors. Here we report the development of a laterally patterned diffusion doping technique which utilizes a batch compatible spinon glass process to achieve spatial control of both p and ntype dopants. This enhanced control allows for the fabrication of nanoelectronic gain elements, such as pn diodes, and npn and pnp transistors, as well as circuits that combine nFET and pFET arrays into mosaics capable of CMOScompatible logic. Here, we use electrostatic force microscopy (EFM) to verify the fidelity of the patterned doping process and characterize active devices, while currentvoltage measurements evaluate junction quality and device performance. [Preview Abstract] 

R1.00094: Glass Nanofiber Fabrication and Devices Scott Verbridge, Joshua Edel, Samuel Stavis, Jose MoranMirabal, Jun Kameoka, David Czaplewski, Haiqing Liu, Harold Craighead, Scott D. Allen, Geoffrey Coates We have integrated electric field assisted spinning (electrospinning) of polymeric materials with photolithography for the fabrication of glass nanostructures. We incorporated spin on glass (SOG) dielectric coating with polyvinylpyrrolidone (PVP) and spun this solution over trenches etched in silicon. A calcination eliminated the PVP polymer from these fibers, while crosslinking the SOG, leaving silica glass fibers with diameters as small as 70 nm. We demonstrated the operation of these fibers as nanomechanical oscillators. We also spun heat depolymerizable polycarbonate (HDPC) fibers over silicon trenches. These fibers were coated with glass by chemical vapor deposition or sputtering, followed by thermal elimination of the polymer core. This yielded suspended glass channels of elliptical cross sections, with inner major and minor axes as small as 75 and 50 nm. These nanochannels offer a low background option for doing fluorescence detection, as demonstrated by single molecule detection, using a confocal microscope, of cellulase enzymes in these channels. [Preview Abstract] 

R1.00095: Electron Energy Structure and Electron Paramagnetic Resonance of Binuclear Niobium Molecules in LiNb Phosphate Glass Dielectrics Sabrina ArringtonPeet, Rakhim Rakhimov, Vladimir Gavrilenko Electron paramagnetic resonance (EPR) spectra of Nb4+ ions in lithiumniobium phosphate glass insulators with different composition of oxide components have been studied. The EPR data reveal formation of triplet Nb binuclear complex in LiNb glass dielectric. Equilibrium atomic geometries of a model molecule (OH)$_{3}$NbONb(OH)$_{3}$ embedded into LiNb phosphate glass are determined by molecular dynamics. The total energy and electron energy structure of the system have been studied by first principles generalized gradient approximation (GGA) method within density functional theory (DFT). Molecular geometry in substantially distorted as a result of external potential of the glass. Total energy analysis of the (OH)$_{3}$NbONb(OH)$_{3}$ molecule embedded into LiNb phosphate glass indicates appearance of two nonequivalent atomic geometries with the oxygen atom in NbONb fragment shifted from its undisturbed symmetrical position. Predicted modifications of electron energy structure of the system are discussed in comparison with measured EPR data. [Preview Abstract] 

R1.00096: Solution of local field equations for selfgenerated glasses Sangwook Wu, Joerg Schmalian, Gabriel Kotliar, Peter Wolynes We present a selfconsistent local approach to selfgenerated glassiness that is based on the concept of the dynamical mean field theory to many body system. Using a replica approach to a selfgenerated glassiness, we map the problem onto an effective local problem that can be solved exactly. Applying the approach to the Brazovskiimodel, relevant to a large class of systems with frustrated microphase separation, we are able to solve the selfconsistent local theory without using additional approximations. We demonstrate that a glassy state found earlier in this model is generic and does not arise from the use of perturbative approximations. In addition we demonstrate that the glassy state is further stabilized by an additional asymmetry in the interaction. [Preview Abstract] 

R1.00097: A high energy xray diffraction study of the atomic structure of novel rare earth ultraphophate glasses Mehdi Ali, Kanishka Marasinghe, Robert Hart, Chris Benmore, Nathan Wyckoff, Richard Brow Rare earth ultraphosphate (REUP) glasses have exciting magnetic and optical properties with numerous potential applications. These properties depend heavily on the atomic structure, especially the rare earth coordination environment. A series of rare earth (namely Neodymium, Gadolinium, and Erbium) ultra phosphate glasses have been studied using high energy (112114 KeV) Xray diffraction technique. A heuristic approach used for determining the appropriate normalization of Xray scattering data and for confirming the sample compositions will be presented. Dependence of the rare earth coordination environment on the type and concentration of the rare earth atoms as determined by these high energy Xray studies will be discussed. [Preview Abstract] 

R1.00098: Simulation of Hydrogen Diffusion in Hydrogenated Amorphous Silicon (aSi:H) from abinitio Molecular Dynamics F. Gaspari, A. Shkrebtii, J. Perz, T. Teatro, N. Kherani The role of hydrogen in hydrogenated amorphous silicon (aSi:H) has been the subject of considerable studies in the past 30 years. In particular the mechanism of hydrogen diffusion and its relation to the bonding structure within the amorphous silicon network is considered to be crucial for the understanding of several properties of aSi:H, including the StaeblerWronski effect. We have investigated hydrogen diffusion in aSi:H using firstprinciples molecular dynamics, by simulating a system of 64 silicon plus 10 neutral hydrogen atoms. The amorphous structure has been verified from the Radial Distribution Function. The dependence of the diffusion of the hydrogen atoms on different bonding configurations has been examined at different temperatures and the results have been correlated with experimental studies of hydrogen, deuterium and tritium effusion. [Preview Abstract] 

R1.00099: Multiscale investigation of low molecular weight glass formers Jayeeta Ghosh, Roland Faller Orthoterphenyl (OTP), a very well known and well investigated organic glass former, is used as a model to study the static and dynamic properties of low molecular weight glass formers. Molecular dynamics is applied to simulate 800 molecules in atomistic detail. The model is able to provide very good agreement with experimental observations. Our simulation gives the glass transition temperature ($\sim$260K) slightly higher than the experimental value (243K) but is much closer to that value than comparable simulations. Radial distribution functions calculated at temperatures above and below the glass transition temperature show that there are no remarkable changes in structure at the molecular level. We study the inhomogeneity at the local level around each molecule and compare static and dynamic heterogeneities. From the radial distribution functions we develop a structural coarse grained model. With this coarser model in which each ring of OTP is considered as one super atom, OTP should provide similar structural and dynamic properties above and below glass transition temperature. Future work on this multiscale approach includes applying the Density of States Monte Carlo technique to this real glass forming organic molecule. This novel Monte Carlo technique has been used for a binary Lennard Jones mixture as model glass former. This would be the first approach to apply it to a real glass forming liquid. We will eventually be able to study the effect of confinement on the transition. [Preview Abstract] 

R1.00100: Multilayer Polymeric Encapsulation of Flexible Organic Photovoltaic Devices Pallavi Madakasira, K. Inoue, S. Lee, A. Zakhidov Flexible solar cells, based on conjugated polymeric DA systems have stimulated considerable interest recently. We obtained efficiencies $\sim $4{\%} in heattreated PHT/PCBM based solar cells [1]. These have the advantage of being mounted easily on either a flat or curved surface. One of the major problems is their protection from degradation due to exposure to air and moisture under intense light irradiation.These necessitate use of flexible encapsulation. Parylene has been used to encapsulate various devices,like OLEDs [2,3]. It is stable when deposited on devices in vacuum. First results on conformal deposition on solar cells is reported here, and effects of protection depending on the thickness of parylene film. It provides pinhole free coating for dielectric protection. [1] K. Inoue, R. Ulbricht, P. C. Madakasira, W.M. Sampson, S. Lee, J. Gutierrez, J. Ferraris and A. A. Zakhidov,Proc. of SPIE  Org. Photovoltaics V, 5520, p.256262 (2004). [2]Z.Zhang, G.Xiao, J.Liu and C.P. Grover, \textit{Fiber and Integrated Optics,22:3433552003} [3] Y.S. Jeong, B.Ratier, A. Moliton and L.Guyard, \textit{Synthetic Materials 127 (2002) 189193} [Preview Abstract] 

R1.00101: Magnetoelectric effect in porous bulk ferromagnetic/piezoelectric composites M. I. Bichurin, V. M. Petrov, D. S. Tuskov, G. Srinivasan Bulk and layered composites of piezoelectric and magnetostrictive phases show magnetoelectric (ME) properties. Bulk composites are desirable over layered samples due to superior mechanical strength. Here we discuss a model that considers the influence of porosity on ME interactions in a bulk composite. The composite is assumed to consist of piezoelectric, magnetostrictive and void (pores) subsystems. We solved combined elastostatic, electrostatic and magnetostatic equations to obtain effective composite parameters (piezoelectric modules, magnetostriction factors, compliances, ME coefficients). Expressions for longitudinal and transverse lowfrequency ME voltage coefficients have been obtained for 3 00 and 030 connectivity types. The dependence for ME voltage coefficient on volume fractions of the two phases are shown to be dependent on connectivity type. The strength of ME interaction depends on porosity. The calculated ME coefficients are in good agreement with data in Ref.1. \begin{enumerate} \item G. Srinivasan, C. P. DeVreugd, C. S. Flattery, V. M. Laletsin and N. Paddubnaya. \textit{Appl. Phys. Lett}., \textbf {85}, 2550 (2004). \end{enumerate}  supported by grants from the Russian Ministry of Education (Å023.4278), the Universities of Russia Foundation (UNR 01.01.026) and the National Science Foundation (DMR0302254). [Preview Abstract] 

R1.00102: Theory of electromechanical resonance in magnetostrictive  piezoelectric multilayer composites D.A. Filippov, V.M. Petrov, M.I. Bichurin, C.W. Nan, G. Srinivasan The theory of electromechanical resonance in multilayer magnetostrictive  piezoelectric composites is developed. The theory is based on the use of initial (not effective) parameters of magnetostrictive and piezoelectric phases. Equations of motion were used to obtain an expression for the frequencydependence of magnetoelectric response in a multilayer composite [1,2]. The enhanced magnetoelectric response at the electromechanical resonance is dependent on the interface coupling. The calculations predict a peak in the magnetoelectric voltage coefficient at electromechanical resonance, with a twoorder of magnitude increase relative to lowfrequency values. These predictions are in agreement with data for ferritelead zirconante titanate (PZT) bilayers and metalPZTmetal trilayers. 1. M. I. Bichurin, D.A. Filippov, V. M. Petrov, V. M. Laletin, N. Paddubnaya, and G. Srinivasan, Phys. Rev., B \textbf{68}, 132408 (2003). 2. D. A. Fillipov, M. I. Bichurin, V. M. Petrov, V. M. Laletsin, N. N. Puddubnaya, and G. Srinivasan, \textit{Magnetoelectric Interaction Phenomena in Crystals}NATO Science Series II. Vol. 164, Eds. M. Fiebig, V. V. Eremenko, and I. E. Chupis (Kluwer Academic Publishers, London, 2004), p.7180.  supported by grants from the Russian Ministry of Education (Å023.4278), the Universities of Russia Foundation (UNR 01.01.026) and the National Science Foundation (DMR0302254). [Preview Abstract] 

R1.00103: Correlation of magnetoelectric and deltaE effects in ferromagneticpiezoelectric layered composites V.M. Laletin, N. Paddubnaya, G. Srinivasan, C.P. DeVreugd, M.I. Bichurin, V.M. Petrov, D.A. Filippov Magnetoelectric (ME) coupling and its dependence on delta$E$effect have been studied in trilayers of ferromagnetic metals and lead zirconate titanate (PZT). Measurements on samples with PZT and Fe, Co, Ni or permendur (an alloy of CoFeV) show evidence for strong ME interactions. Our theoretical model for bias magnetic field H dependence of ME effect predicts contributions due to two mechanisms: variation of piezomagnetic and compliance coefficients with H. The individual contributions from the two sources can be measured in the electromechanical resonance (EMR) region for the composite. Data on frequency dependence of ${\rm M}{\rm E}$ coefficient reveal a giant coupling at electromechanical resonance (EMR), at 200300 kHz for radial modes and at $\sim $2.7 MHz for thickness modes. Variation of compliance coefficients with H (deltaEeffect) results in a frequency shift of peak ME voltage coefficient. Theoretical profiles of ${\rm M}{\rm E}$ coefficient vs. frequency agree with the data. These results are of importance for the design of signal processing devices that requires fine tuning. 1. M. I. Bichurin, D.A. Filippov, V. M. Petrov, V. M. Laletin, N. Paddubnaya, and G. Srinivasan, Phys. Rev. B \textbf{68}, 132408 (2003).  supported by grants from the Russian Ministry of Education (Å023.4278), the Universities of Russia Foundation (UNR 01.01.026) and the National Science Foundation (DMR0302254). [Preview Abstract] 

R1.00104: Modeling of Magnetostriction in Particulate Composite Materials Zhou Yan, F.G. Shin The objective of the present work is to develop a conceptually simple and convenient approach to magnetostriction for particulate composites of magnetostrictive polycrystalline inclusions in elastically isotropic matrices applicable to the whole range of volume fraction of the inclusions, since these composites are often fabricated with a high content of magnetostrictive particles. For illustrative purposes, the calculation for the magnetostriction of composites containing TerfenolD or Nickel are presented. Beginning with the basic elasticity and magnetostriction equations, we use a selfconsistent model to calculate the effective elastic and magnetostrictive behaviors of Nickel/epoxy and TerfenolD/glass composites. The longitudinal magnetostriction of pure polycrystalline TerfenolD is deduced from the experimental data of the composite having 60{\%} volume fraction of TerfenolD; Nickel data is taken from literature. Through numerical calculation, we have obtained the macroscopic longitudinal strains parallel to the applied magnetic field for TerfenolD/glass composites and both longitudinal and transverse strains for the Nickel/epoxy composites. Goodness of fit for both material systems shows our model is applicable up to very high volume fraction of inclusions. Our magnetostriction model can be useful in providing a general guide for the evaluation and technical improvement of magnetostrictive composites currently under development. [Preview Abstract] 

R1.00105: {\em Ab initio} study of the structure of 1,3butadiene on a Si(001) surface Kijeong Kong, BeyongHwan Ryu, Youngmin Choi, JeongO Lee, Kiseok Ahn, Hyunju Chang By employing {\em ab initio} totalenergy calculations we have studied the adsorption of 1,3butadiene molecule on a dimerreconstructed Si(001) surface. We have found that the [4+2] products are thermodynamically more stable than the [2+2] products. There are basically two kinds of [4+2] products: (i) the wellknown ontop di$\sigma$ configuration over a single dimer and (ii) endbridge configurations occupying two successive dimers in the same dimer row. In [EB] configuration at one ML coverage, 1,3butadiene molecules at opposite end of dimer bond together to form cubane (C$_8$H$_8$)like square geometry with one hydrogen atom at each apex, which is stabilized by the full compensation of dangling bonds and converting two $\pi$bonds to two $\sigma$bonds. The staggered endbridge (s[EB]) is also stable by strain release. By comparing the simulated STM images and experimental ones, we pointed out that the [EB] configuration shows similar feature to that attributed as [2+2] configuration in previous experiments. The calculated corelevel shifts(CLS) of C $1s$ orbital show little difference between peak from interface C atom bonded directly to silicon and that from surface C atom with unsaturated double bond. [Preview Abstract] 

R1.00106: A Simple ``Sticky Disc'' Model for Crystalline and Amorphous Networks Adrian Huerta, Nikita Chubynsky, Gerardo Naumis, Michael Thorpe Using Monte Carlo simulations, we study the structural and thermodynamic behavior of a simple one component network forming model made up of ``sticky discs.'' Central and bond bending forces was included, modeling such interactions as a simple square well radial and angular three body term in the potential respectively. The main feature of this model is the ability to form crystalline and amorphous networks upon cooling, similar to that obtained using the so called WWW methodology to describe the network of some vitreous structures [1]. With the ``pebble game'' algorithm [2], we evaluate the number of degrees of freedom and the amount of stress in both the amorphous and crystalline structures. We discuss the connection between the configurational entropy (associated with the topology) and the degrees of freedom. Other effects such as elasticity of these structures are also discussed. \\ 1. Wooten, F., Winer, K. and Weaire, D., Phys. Rev. Lett., 54 1392 1395 (1985). \\ 2. Jacobs, D.J. and Thorpe, M.F., Phys. Rev. Lett., 75 4051 4054 (1995). [Preview Abstract] 

R1.00107: MAGNETISM (EXPERIMENT, THEORY, APPLICATIONS) 

R1.00108: Magnetizationinduced Secondharmonic Generation in FeAu Alloy Films and Fe/Au Multilayered Films Y.H. Hyun, J.Y. Kim, G.J. Lee, Y.P. Lee, K.W. Kim The surfaces and the interfaces of magnetic films were investigated by using magnetizationinduced secondharmonic generation (MSHG). Fe$_{x}$Au$_{1x}$ (0 $< x <$ 1) alloy films of about 100  150 nm in thickness and (3.0 nm Fe/ $t _{Au}$)$_ {20}$ multilayered films (MLF) ($t_ {Au}$ = 1.0  3.0 nm) were prepared by rfsputtering on glass substrates at room temperature. The structures and the magnetic hysteresis loops of FeAu alloy films and Fe/Au MLF were measured by xray diffraction and vibrating sample magnetometry (VSM), respectively. The magnetooptical Kerr effect (MOKE) was obtained in the equatorial mode and the MSHG measurements were also performed in the longitudinal mode. The MSHG results are analyzed in connection with the MOKE and the VSM results. [Preview Abstract] 

R1.00109: Effects of Dilution on the Phase Behavior of Antiferromagnetic Ultrathin Magnetic Films Stefan Patchedjiev, John Whitehead, Keith De'Bell The effects of dilution on the ground states of magnetic rotors for the two and three dimensional Heisenberg model are studied using Monte Carlo simulations. In these models the classical spins are distributed on a square twodimensional lattice, and interact through nearestneighbor antiferromagnetic exchange and dipolar interactions, in the presence of vacancies. The phase diagrams for both systems are presented as a function of the ratio of $\vert $J$\vert $/g for different dilutions. The results indicate that for low temperature the randomly distributed vacancies, through the phenomenon 'order due to disorder', lead to richer phase space. [Preview Abstract] 

R1.00110: Quantum electron dynamics with spin orbit interaction in one dimensional periodic sequences Ramon Carrillo, Fernando Rojas The electron dynamics in onedimensional periodic crystals presents important effects such as ballistic motion, Bloch oscillations and dynamic localization. We are interested in evaluate how these effects are modified if ones includes the spin degree of freedom. In this work, we study the electron dynamics with spin orbit interaction (SOI) in onedimensional periodic crystals, using the singleband tightbinding model. The model includes besides the nearest neighbors tunneling, the spinorbit interaction through a spin rotation when hopping the electron. We determine the time dependence of the probability per site, the meansquare displacement, the magnetization per site and the Shannon entropy for each spin (up and down). The meansquare displacement per spin shows coherent oscillations between up and down band superposed to the ballistic behavior characteristic of the case without SOI. The total mean square displacement is proportional to the square of the SOI plus tunneling amplitudes. We also found that the coherent oscillation between spin bands is also present in the other properties. We also study the effect of SOI on Bloch oscillations due the presence of an dc electric field and calculate the same properties. The work is supported by DGAPA project IN114403 and CONACyT project 43673F [Preview Abstract] 

R1.00111: Low Temperature Phase Diagram in $\gammap$NPNN Koichi Kajiyoshi, Takashi Kambe, Kokichi Oshima We performed the magnetic torque measurements of $\gamma $phase of \textit{para}Nitrophenyl Nitronyl Nitroxide (being $p$NPNN), which is considered to be as a quasionedimensional ferromagnet, in the vicinity of $T_{N}$ (=0.65K) using a piezoresistive microcantilever. Typical sample dimension is about $0.25\times 0.10\times 0.10$mm$^{3}$. At 0.4K, a spinflop transition ($H_{SF})$ and an antiferromagneticparamagnetic transition ($H_ {C})$ are clearly observed in the magnetic field of about 470 Gauss and 2100 Gauss, respectively. The spineasy axis is almost parallel to the direction to phenyl ring from the ONCNO fragments. $HT$ phase diagram is determined properly. These results are consistent with our recent low frequency ($\sim $ 300 MHz) and lowtemperature (0.4 K) ESR. We will discuss the $HT$ phase diagram of $\gamma p$NPNN in comparison with the one dimensional Heisenberg ferromagnetic model. [Preview Abstract] 

R1.00112: Hidden Magnetic Order in Quantum Spin Chains Changfeng Chen We report on a study of the hidden magnetic order and the associated topological structure in antiferromagnetic Heisenberg chains with general spins. We show that rich topological structures with intriguing physical properties manifest on the macroscopic length scale but disappear on the infinite length scale in chains with halfinteger spins. It demonstrates that the macroscopic length scale is not a very large length scale in this problem and must be treated separately from the infinite length scale that is often taken as an substitute for the macroscopic thermodynamic limit. We reveal a concept of multiple length scales in describing the topological structures in quantum spin chains. [Preview Abstract] 

R1.00113: Magnetic Ordering in La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ Films Driven by Nanostructural Disorder V. G. Prokhorov, Y. P. Lee, S. Y. Park, J. S. Park Completely amorphous, partly disordered (a perfect crystalline matrix with randomlyoriented nanocrystalline inclusions), and latticestrained La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ films were prepared by rf magnetron sputtering. The amorphous film demonstrates a temperaturedependent magnetization, typical for the paramagnet with freelymoving individual Mn spins. The partly disordered film represents a superposition of the ferromagnetic (FM) phase, which belongs to the crystalline matrix, and the superparamagnetic (SPM) one, corresponding to the nanocrystalline inclusions. Analysis of the magnetic hysteresis loops reveals that about 70\% of the film volume belongs to the FM phase. It was shown that the average magnetic moment of SPM particles is controlled by an applied magnetic field, which is explained by a partial SPM to FM transition due to an enhancement of the ferromagnetic coupling between adjacent nanocrystalline clusters. The latticestrained film turns out to be in an inhomogeneous FM state. [Preview Abstract] 

R1.00114: A Dilute ThreeDimensional XY Ferromagnet G.C. DeFotis, T.R. Leftwich, R.A. Huddleston, B.C. Rothermel, J.H. Boyle, E.S. Vos Iron(III) bis(diselenocarbamate) chloride is a pentacoordinate molecular ferromagnet ordering near 3.4 K. The unusual site symmetry yields a spin 3/2 ground state. A rather substantial zerofield splitting occurs, with D positive, leading to XY like magnetic properties at low temperature. Significant exchange interactions occur between molecules via FeSe...SeFe contacts, without substantial spatial anisotropy. It is of interest to examine the effects of diamagnetic dilution on such a system. We have succeeded in dissolving modest amounts of diamagnetic Zn(II) bis(dithiocarbamate) into the Fe(III) system lattice. Analysis of susceptibility and magnetization data reveals a sizable reduction of the magnetic ordering temperature of the pure material on dilution. Comparisons are possible with previous work in which dilution of the approximate 3DIsing system Fe(III) bis(dithiocarbamate) chloride was studied. *Supported by NSFSolid State ChemistryGrant No. DMR0085662 and by a grant from the Petroleum Research Fund of the American Chemical Society. [Preview Abstract] 

R1.00115: Magnetic properties of a new onedimensional vanadium oxide with the hollandite structure Natasha A. Chernova, J. Katana Ngala, Peter Y. Zavalij, M. Stanley Whittingham The magnetic properties of the first hollanditetype vanadium oxide V$_{7.22}$O$_{8}$(OH)$_{8}$(Cl)$_{0.77}$(H$_{3}$O)$_{2.34}$ containing anions in the tunnels are studied. The temperature dependence of the static magnetic susceptibility reveals a magnetic phase transition at about T$_{c}$=20 K. Below this temperature, fieldcooled and zerofieldcooled susceptibilities diverge. The temperature dependencies of the dynamic ac susceptibility show maximum at T$_{c}$, that shifts toward lower temperatures with decreasing ac frequency; an additional maximum is observed at 7 K. The analysis of the frequency dependency of the ac susceptibility reveals the presence of three relaxation processes. The temperature dependencies of their relaxation times are determined using ColeCole analysis. The slowest relaxation process is characterized by the scaling law with the dynamical critical exponent z$\nu $=8, and the characteristic relaxation time about 6$\times $10$^{4}$ s. The magnetic properties of the compound are explained using randomfield Ising model, with randomness brought on by vacancies in vanadium sites. The relaxation processes observed are related to the fluctuations of the magnetic moment of various size clusters. This work was supported by NSF DMR 0313963. [Preview Abstract] 

R1.00116: NonContact Laser Based Ultrasound Evaluation of Canned Foods David Shelton LaserBased Ultrasound detection was used to measure the velocity of compression waves transmitted through canned foods. Condensed broth, canned pasta, and noncondensed soup were evaluated in these experiments. Homodyne adaptive optics resulted in measurements that were more accurate than the traditional heterodyne method, as well as yielding a 10 dB gain in signal to noise. AScans measured the velocity of ultrasound sent through the center of the can and were able to distinguish the quantity of food stuff in its path, as well as distinguish between meat and potato. BScans investigated the heterogeneity of the sample’s contents. The evaluation of canned foods was completely noncontact and would be suitable for continuous monitoring in production. These results were verified by conducting the same experiments with a contact piezo transducer. Although the contact method yields a higher signal to noise ratio than the noncontact method, LaserBased Ultrasound was able to detect surface waves the contact transducer could not. [Preview Abstract] 

R1.00117: Renormalization group method for weaklycoupled quantum chains: application to the spin onehalf Heisenberg model Samuel Moukouri, Jose Alvarez, Porscha McRobbie The KatoBloch perturbation formalism is used to present a densitymatrix renormalizationgroup (DMRG) method for strongly anisotropic twodimensional systems. This method is used to study Heisenberg chains weakly coupled by the transverse couplings $J_{\perp}$ and $J_{d}$ (along the diagonals). An extensive comparison of the renormalization group and quantum Monte Carlo results for parameters where the simulations by the latter method are possible shows a very good agreement between the two methods. It is found, by analyzing ground state energies and spinspin correlation functions, that there is a transition between two ordered magnetic states. When $J_{d}/J_ {\perp} \alt 0.5$, the ground state displays a N\'eel order. When $J_{d}/J_{\perp} \agt 0.5$, a collinear magnetic ground state in which interchain spin correlations are ferromagnetic becomes stable. In the vicinity of the transition point, $J_ {d}/J_{\perp} \approx 0.5$, the ground state is disordered. But, the nature of this disordered ground state is unclear. While the numerical data seem to show that the chains are disconnected, the possibility of a genuine disordered two dimensional state, hidden by finite size effects, cannot be excluded. [Preview Abstract] 

R1.00118: Spin dynamics algorithms for systems with exchange interactions beyond nearest neighbors Xiuping Tao, D. P. Landau, T. C. Schulthess, G. M. Stocks Fast spin dynamics algorithms for classical spin systems with nearest neighbor exchange interactions ($J_1 \neq 0$, and $J_i = 0$ for $i^{th}$ nearest neighbors with $i \geq 2$ ) were studied extensively years ago\footnotemark[2].\footnotetext[2]{M. Krech, A. Bunker, and D. P. Landau, Comput. Phys. Commun. {\bf 111}, 1 (1998).} For some realistic magnetic systems, such as Fe, $J_i$ can not be neglected for several shells of neighbors. To study dynamic properties of such systems, fast algorithms are still applicable; however, with $n$ shells of interacting neighbors, a lattice needs to be decomposed into $2^n$ sublattices and there can be as many as $(5^{2^{n}}3)/2$ factors for the fourth order SuzukiTrotter decompositions of exponential operators. In comparison, only $2^{n+1}1$ factors are needed for second order decompositions. Consequently, only second order decompositions are practical for $n\geq 2$. Examples are given showing the implementation of the algorithms for systems in which as many as four shells of near neighbors play a significant role. [Preview Abstract] 

R1.00119: Longitudinal and transverse components of the complex magnetic susceptibility tensor of superparamagnetic particles with triaxial anisotropy Yuri Kalmykov, Bachir Ouari, William Coffey The longitudinal and transverse components of the complex magnetic susceptibility tensor of single domain ferromagnetic particles with triaxial (orthorhombic) anisotropy are calculated by averaging the GilbertLangevin equation for the magnetization of an individual particle and by reducing the problem to that of solving a system of linear differential recurrence relations for the appropriate equilibrium correlation functions. The solution of this system is obtained in terms of matrix continued fractions. Simple analytic equations, which allow one to understand the qualitative behavior of the system and to accurately predict the spectrum of the longitudinal and transverse complex susceptibilities in wide ranges of the barrier height and dissipation parameters, are proposed. [Preview Abstract] 

R1.00120: Preparation and Characterization of Fe and FeNi Perm Alloy Magnetic Nanoparticles embedded in a Thin Polymer Films T. Kehl, B. Robertson, C. Vera, L. Fadiga, K. Paul, T. Kassim, K. Ghosh, R. Patel, M. Curry, R. Giedd, S. Mishra The nanoparticles of Fe and FeNi Perm Alloy were prepared via bombarding high energy nitrogen ions with dose of 1x 10$^{16}$ ion cm$^{2}$ at room temperature on a polymer poly ether ether ketone (PEEK) sheet predeposited with different thickness (20 to 100 A) of magnetic thin film. The microstructure of nanoparticles was studied by scanning electron microscope, transmission electron microscope, and magnetic force microscopy. The structural evaluation of the composite via TEM suggests the presence of very fine nanoparticles in the rage of 1020 nm embedded in polymer matrix. Room temperature magnetotransport measurement indicates negative magnetoresistance and the value of MR depends on the size of the nanoparticles. Hall magnetometery shows that as the particle size decreases the behavior of the sample changes from ferromagnetic to superparamagnetic. In this presentation many of unique electrical and magnetic properties of magnetic nanocomposite thin films produced by ion implantation will be discussed in detail. [Preview Abstract] 

R1.00121: The Characteristics of Irondoped Barium Titanate Nanocrystals Christina Arthur Barium Titanate BaTiO$_{3 }$is known for both its electric and magnetic properties and the applications are presumed to be greater in the nanoscale region. The synthesis and characterization of iron doped barium titanate nanocrystallites; BaTi$_{1x}$Fe$_{x}$O$_{3}$ (0$\le $ x $\le $ 1) was investigated with a view to understand its structural and magnetic properties. The samples were synthesized using a wet chemical technique followed by a high temperature and highpressure hot isostatic pressing treatment. Powder Xray diffractograms of the samples indicated the purity and scanning electron microscope images were used to determine the particle size. $^{57}$Fe M\"{o}ssbauer spectral data suggest the presence of ferrous and ferric species substituted in the lattice points of titanium. Details of the preparation technique, experimental results, data analysis, and the interpretation will be presented. [Preview Abstract] 

R1.00122: Crystallization behavior of mechanically milled nanocomposite PrFeB alloys George Hadjipanayis, Melania Marinescu, Yong Zhang, Alexander Gabay In the past few years, research studies have proposed the high energy mechanical milling as an alternative route to the melt spinning for the development of nanocomposite twophase 2:14:1 / bcc Fe magnets. The current work presents our results on Pr$_{9}$Fe$_{85}$B$_{6}$ and Pr$_{9}$Dy$_{1}$Fe$_{76}$Co$_{8}$Si$_{1}$B$_{5}$ mechanically milled powders with emphasis on the microstructure peculiarities, phase transformations upon annealing and their relation with the magnetic properties. Calorimetric investigations in asmilled powders show a main exothermic peak occurring at relatively low temperatures (350$^{\circ}$C) that has been associated with a stressrelief effect. HRTEM micrographs for asmilled powders give evidence of coexistence of bcc Fe or (Fe,Co) phase (d$_{g}\cong $1015 nm), and an amorphous phase. The amorphous phase is still observed in powders annealed at 400$^{\circ}$C and coexists with slightly enlarged bcc Fe or (Fe,Co) grains (d$_{g}\cong $1520 nm) and with a newly precipitated 1:7type phase. A high degree of strain is present in the nanograins. The microstructure becomes free of internal stresses and completely crystallizes at 650$^{\circ}$C. The extrinsic magnetic properties are strongly related to the powder microstructure. [Preview Abstract] 

R1.00123: Magnetic Properties of Vanadiumdoped La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ K. H. Han, S. Y. Park, K. K. Yu, J. S. Park, Y. P. Lee The magnetic properties of La$_{0.7}$Ca$_{0.3}$Mn$_{x}$V$_{1x} $O$_{3}$ (LCMVO) were investigated. Polycrystalline LCMVO samples were synthesized by the standard solidstate reaction. The Curie temperature was found to decrease with increasing the content of vanadium. The spinglasslike phenomenon has been observed in the Vdoped samples. A sharp drop of the zerofield cooled magnetization at $T$ $\sim$ 80 K implies a spinfreezing behavior. The temperature dependence of coercivity for La$_{0.7} $Ca$_{0.3}$Mn$_{0.9}$V$_{0.1}$O$_{3}$ shows a cusp at about 80 K, which is almost identical to the aforementioned spinfreezing temperature. The effective anisotropy energy of magnetic clusters in the samples was also estimated from the initial magnetization curves. It is suggested that the temperature dependence of coercivity for La$_{0.7}$Ca$_{0.3}$Mn$_{0.9}$V$_ {0.1}$O$_{3}$ is related to coexistence of the ferromagnetic and the antiferromagnetic orders, which is induced by the V doping at the Mn sites. [Preview Abstract] 

R1.00124: Peculiar Magnetic Properties of Polycrystalline La$_{1x}$Sr$_{x}$CoO$_{3}$ K. K. Yu, J. S. Park, Y. P. Lee, Y. S. Lee, J. H. Kang Polycrystalline La$_{1x}$Sr$_{x}$CoO$_{3}$ samples were synthesized by the standard solidstate reaction. The xray diffraction (XRD) measurement was performed at each step of the preparation to monitor the progress of reaction. The ferromagnetic transition temperatures were obtained from the a.c. susceptibility measurement, and the temperature dependence of magnetization was measured by using a superconducting quantum interference device (SQUID) magnetometer. The structural and the magnetic orderings at low temperatures were further investigated by neutron diffraction. It was found that the antiferromagnetic and the ferromagnetic states coexist at low temperatures. This anomalous magnetic behavior can be explained by the existence of ferromagnetic grains in the nonferromagnetic matrix. [Preview Abstract] 

R1.00125: Spinpolarized electron states in a quantum film based on narrow  band semiconductors Leonid Isaev, Yong Joe, Arkady Satanin, Sergio Ulloa Narrowgap semiconductors (NGS) with strong spinorbit interactions are promising materials as a source of polarized electrons. Electron states in NGS are described by the Diractype equation with Hamiltonian parameters determined by the Kane interband matrix element [1]. Modern epitaxial technology makes it possible to create quantum films (QF) (or quantum wells) with a \textit{given }spatial dependence of the composition, $i.e$. control of the positiondependence of the energy gap. The electron dispersion in a homogeneous QF with same boundaries still keeps the spin degeneracy [2]. In the present work it is shown that the position dependent gap leads to spinsplitting of the electron dispersion in a QF. For a film with a \textit{linear} spatial gap variation in the transverse direction, the solution of the Dirac equation can be found exactly. Near the gap the proposed spinorbit mechanism approximately reduces to Rashba's term with the loop in dispersion. The electron polarization degree for a QF based on a \textit{Pb}$_{1x}$\textit{ Sn}$_{x}$\textit{ Te} system is calculated. [1] J. O. Dimmock \textit{et al}, Phys. Rev. \textbf{16}, 1193 (1966). [2] S.Yu. Potapenko and A. M. Satanin, Sov. Phys. Solid State \textbf{26}, 1067 (1984). [Preview Abstract] 

R1.00126: Monte Carlo Simulations of Diluted Magnetic Semiconductors J. Rufinus We have performed Monte Carlobased simulations of Diluted Magnetic Semiconductors materials in a large scale three dimensional cube with periodic boundary condition. We present the preliminary results of our study of the transition temperatures of these materials. We also compared our results with those obtained using mean field theory. [Preview Abstract] 

R1.00127: Influence of Hydrostatic Pressure on Transport Properties of Sb$_{2x}$V$_{x}$Te$_{3}$ and Ga$_{1x}$Mn$_{x}$As J.S. Dyck, T.J. Mitchell, P.A. Speero, M.C. Aronson, C. Uher, C. Drasar, P. Lostak, X. Liu, J.K. Furdyna We present results on the transport properties of two types of ferromagnetic diluted magnetic semiconductors (DMS) under hydrostatic pressures up to 1.6 GPa. High pressure measurements afford a reversible way to tune both the electronic structure and magnetic interactions of these materials. The behavior of the Curie temperature can be monitored via the position of the peak in the resistance data associated with the ferromagnetic transition. In the case of Sb$_{2x}$V$_{x}$Te$_{3}^{ }$with x = 0.03, pressure strongly affects the electrical resistivity and Curie temperature. For Ga$_{1x}$Mn$_{x}$As with x = 0.09, little change is seen in the properties. Measurements in magnetic field will also be presented and discussed. [Preview Abstract] 

R1.00128: Comparative study of ferromagnetism in dilutely Cr, V, Co and Fe doped TiO$_{2}$ films I. Satoh, S. Zhang, S. R. Shinde, S. Dhar, M. S. R. Rao, D. C. Kundaliya, S. B. Ogale, T. Venkatesan, S. Lofland Epitaxial thin films of TiO$_{2}$ dilutely doped with Cr, V, Co and Fe are grown on LaAlO$_{3}$ (LAO) and sapphire substrates under different growth conditions. The films on LAO are anatase while those on sapphire are rutile. Occurrence of ferromagnetism, the magnetic moment, temperature dependence of magnetization, and concentration dependence of the saturation moment and coercive field are examined for Cr, V and Fe doped films, and compared with the well studied case of Co:TiO$_{2}$. Various techniques such as xray diffraction, SQUID magnetometry, vibrating sample magnetometry, and Rutherford backscattering channeling are used. The magnetic moment appears in the Cr doped anatase TiO$_{2}$ grown at 850 $^{0}$C at oxygen pressure of 10$^{5}$ Torr, but the film is insulating in nature. No moment is seen in the conducting film grown at lower temperature of 700 $^{0}$C. The growth condition and concentration dependence in this and other systems exhibit interesting features, which are analyzed in terms of the new models of ferromagnetism involving the role of defects and polaronic states. [Preview Abstract] 

R1.00129: Magnetoelastic effects in Sm2IrIn8 R. LoraSerrano, C. Giles, E. Granado, P.G. Pagliuso, J.L Sarrao In this work we report the results of high resolution temperature dependence Xray diffraction measurements taken on single crystals of Sm$_{2}$IrIn$_{8}$ at the XRD2 beamline of Laboratorio Nacional de Luz Sincrotron (LNLS), in Campinas, Brazil. Our data reveal the existence of a magnetostrictive tetragonaltoorthorhombic phase transition at 14.2 K coincidently to the first order antiferromagnetic transition. For T$<$T$_{N}$ the mismatch between the $a$ and $b$ lattice parameters increases continuously with decreasing temperature up to a value of $\raise0.7ex\hbox{$a$} \!\mathord{\left/ {\vphantom {a b}}\right.\kern\nulldelimiterspace}\!\lower0.7ex\hbox{$b$}1\approx $ 0.44 {\%} at the lowest temperature measured, T = 10K. [Preview Abstract] 

R1.00130: Hydrodynamic model for spinpolarized transport in semiconductors Leonardo VillegasLelovsky, Fabricio M. Souza, J. Carlos Egues We extend the hydrodynamic model of the Boltzmann equation to account for the spin of the carriers to investigate the transient dynamics of a spinpolarized packet of electrons in a nGaAs sample. The dynamics of the packet as well as the builtin electric field is described by a set of coupled differential equations based on the moments of the Boltzmann equation [1] and the Poisson's equation. Spinflip and momentumrelaxation processes are taken into account within the relaxation time approximation. Our description goes beyond the usual driftdiffusion type approaches in that we fully account for the temporal evolution of the current densities. The spatiotemporal landscape of the current spin polarization shows a transient region within the hydrodynamic model, not present in the driftdiffusion description. We applied our approach in particular for a (n/n+/n)GaAs junction that turned out to be an electrostatic trap with enhanced spin polarizations. [1] F. M. Souza and J. C. Egues, Phys. Rev. B \textbf{66}, 060301(R) (2002). [Preview Abstract] 

R1.00131: $^{11}$B Nuclear Magnetic Resonance Study of Ferromagnetic CaB$_6$ Moohee Lee, Kyuhong Lee, K. H. Kang, B. J. Mean, J. S. Rhee, B. K. Cho We have performed $^{11}$B nuclear magnetic resonance(NMR) measurements to microscopically investigate an electronic structure of the ferromagnetic state in CaB$_6$ single crystals. Although the crystal structure of CaB$_6$ is cubic and three NMR lines are usually expected for the nuclear spin 3/2 of $^{11} $B, a larger number of NMR resonance peaks have been observed. The frequency and intensity of those peaks distinctively changes depending on the angle between crystalline axis and magnetic field. Analyzing this behavior, we find that the electric field gradient(EFG) tensor at the boron has its principal axis perpendicular to the six cubic faces with a quadrupole resonance frequency $\nu_Q \approx$ 600 kHz. Even though the magnetization data highlight the ferromagnetic hysteresis, $^{11}$B NMR linewidth data show no clear microscopic evidence of the ferromagnetic state in several different compositions of CaB$_6$ single crystals. [Preview Abstract] 

R1.00132: Fabrication and Characterization of Microstructured Magnetic thin films Y.C. Chang, J.Y. Ou, Lance Horng, J.C. Wu, ZungHang Wei, MeiFeng Lai, ChingRay Chang Patterned magnetic thin films have been of great interest due to their potential uses in ultrahigh density data storage as well as magnetic field sensors. However, as the size becomes smaller and smaller towards nanometer scales, the shape anisotropy effect turns out to be crucial among all magnetic anisotropies. Herein, we present a systematic study on the magnetic domain configurations and magnetoresistance curves of laterally microstructured permalloy thin films having thickness ranging from 10 to 100 nanometers and various shapes of ellipse and rectangle arrays with aspect ratios ranging from 1 to 12. A commercial scanning electron microscope modified for direct writing was used to define microstructured patterns. The permalloy film was thermally evaporated in the absence of any external magnetic field. Finally, the patterned films were transferred through a liftoff process in acetone. The magnetic domain configurations were imaged by using a Digital Instruments made magnetic force microscope (MFM) at the remanent states as well as insitu under external magnetic fields applied in the film plane. A homemade high coercivity CoPtcoated magnetic tip was used to avoid any effects from the stray fields of patterned films and the external magnetic fields. The MR measurements were carried out at room temperature using a standard fourterminal technique. Details of the MFM images and MR curves will be presented and discussed. [Preview Abstract] 

R1.00133: Magnetization study on FerroAntiferromagnetic Superlattices based on Manganites of the type $La_{x}Ca_{1x}MnO_{3}$ Gloria Campillo, Axel Hoffmann, Pedro Prieto, Maria Elena G\'omez Magnetization measurements were done on a series of La$_{2/3}$Ca$_{1/3}$MnO$_{3}$ ferromagnetic (F) / La$_{1/3}$Ca$_{2/3}$MnO$_{3}$ antiferromagnetic (AF) superlattices, which were prepared with a constant thickness of 3.9 nm for the F layer and thickness of the AF layer was varied in the range $3.9 nm \leq t_{AF} \leq 15.6 nm$. We observe from magnetothermal zero field cooling (ZFC) and field cooling (FC) curves, a bifurcation temperature $T_{bif}$, around 180 K identical for all samples. However, the F Curie temperature $T_{C}$ changes with AF layer thickness. Hysteretic loop measurements after field cooling (FC), from room temperature to 5 K exhibit an exchange bias loop shift, $H_{ex}$, which persists up to temperatures around the Néel temperature $T_{N}$, (~150 K) of the AF layer. The temperature parameter $T_{0}$, derived from an exponential fit of $H_{ex}$, increases with $t_{AF}$ up to approximately 32 K, which is well below the blocking temperature $T_{B} \approx T_{N}$. This result can be associated with a continuous distribution of $T_{B}$ caused by inhomogeneities at the interfaces, and suggests that AF/F interfaceeffects are of critical importance for exchange biasing in LaCaMnO based multilayers. This work was supported by COLCIENCIAS project 11060511458 CT0462002 and US DOEBES. [Preview Abstract] 

R1.00134: Fabrication of Microstructured Magnetic Arrays Using Si$_3$N$_4$ Membrane Mask J.Y. Ou, C.T. Chao, I.C. Lo, J.C. Wu We present a novel technique for the fabrication of microstructured magnetic thin film arrays without standard lithography process. The patterned magnetic arrays in the scale of micrometers have been fabricated by thermal evaporation through Si$_{3}$N$_{4}$ membrane mask. First, a standard photolithography together with wet etching was used for making Si$_{3}$N$_{4}$ membrane. A commercial scanning electron microscope modified for direct writing in combination with reactive ion etching was then employed to create micrometer holes array through Si$_{3}$N$_{4}$ membrane. Finally, permalloy thin films were evaporated onto a silicon substrate with Si$_{3}$N$_{4}$ membrane mask attached on the top. In such a way, various film thicknesses can be made without lithographic process. A magnetic force microscope equipped with a homemade electromagnet was used to explore the remanent magnetic configurations as well as magnetization reversal on the patterned films. [Preview Abstract] 

R1.00135: A 30GHz Hexagonal Ferrite Phase Shifter A. S. Semenov, S. F. Karmanenko, B. A. Kalinikos, A. N. Slavin, G. Srinivasan, J. V. Mantese Highlyanisotropic hexaferrites, such as barium ferrite BaFe$_{12}$O$_{19}$ (BFO), are ideal for millimeter wave phase shifters due to a large ferromagnetic resonance frequency at low magnetic bias field $H$. It enables one to make millimeterwave devices with compact magnetic systems. Here we discuss the design, fabrication and characterization of a BFO phase shifter. A microstrip line deposited on a ferrite substrate supports the propagation of electromagnetic wave, leading to a phase shift \textit{kb, }where $k$ is the wave number and $b$ is the length of the microstrip line. As $k$ is a function of the bias $H$, we obtain a differential phase shift with a change of $H$. A phase shifter consisting of a single crystal (7 x 7 x 0.5 mm$^{3})$ BFO and a 500 $\mu $m wide stripline was evaluated at 30 GHz. A differential phase shift of 30 deg. was measured for H=1.2 kOe. The measured value of the insertion loss was about 10 dB. Work supported by a grant from the Delphi Automotive Corporation. [Preview Abstract] 

R1.00136: Comparative Study of PMA of Fe/Tb and Fe/Gd Multilayers Ataur Chowdhury, Andrea Freitag To study the influence of uniaxial anisotropy of rareearth metals on the perpendicular magnetic anisotropy (PMA) multilayers of Fe/Tb and Fe/Gd were fabricated with magnetron sputtering. Extreme care was taken to fabricate multilayers of Fe/Tb and Fe/Gd with approximately equal layer thicknesses. The samples were studied Mossbauer spectroscopy and torque magnetometer. For samples with very thin layers of Tb and Gd, Mossbauer study shows that the magnetic moments of iron are oriented normal to the surface of the samples. And with increasing layer thicknesses the moments become oriented parallel to the surface of the samples. Magnetic anisotropy constants, measured with torque magnetometer, reveal similar behavior for Fe/Tb and Fe/Gd samples with equal layer thicknesses. The combined results of Mossbauer and torque magnetometer suggests that the uniaxial anisotropy of the rareearth metals, which is very large for Tb ions and quite insignificant for Gd ions, does not contribute to the perpendicular magnetic anisotropy of transitionmetal/rareearth multilayers. [Preview Abstract] 

R1.00137: Magnetization study on FerroAnti\ferromag\netic based on Manganites of the type $La_{x}Ca_{1x}MnO_{3}$ Gloria Campillo, Axel Hoffmann, Pedro Prieto, Maria Elena G\'omez Magnetization measurements were done on a series of $La_{2/3}Ca_{1/3}MnO_{3}$ ferromagnetic (F) / $La_{1/3}Ca_{2/3}MnO_{3}$ antiferromagnetic (AF) superlattices, which were prepared with a constant thickness of 3.9 nm for the F layer and thickness of the AF layer was varied in the range $3.9 nm \leq t_{AF} \leq 15.6 nm$. We observe from magnetothermal zero field cooling (ZFC) and field cooling (FC) curves, a bifurcation temperature $T_{bif}$, around 180 K identical for all samples. However, the F Curie temperature $T_{C}$ changes with AF layer thickness. Hysteretic loop measurements after field cooling (FC), from room temperature to 5 K exhibit an exchange bias loop shift, $H_{ex}$, which persists up to temperatures around the Néel temperature $T_{N}$, (~150 K) of the AF layer. The temperature parameter $T_{0}$, derived from an exponential fit of $H_{ex}$, increases with $t_{AF}$ up to approximately 32 K, which is well below the blocking temperature $T_{B} \approx T_{N}$. This result can be associated with a continuous distribution of $T_{B}$ caused by inhomogeneities at the interfaces, and suggests that AF/F interfaceeffects are of critical importance for exchange biasing in LaCaMnO based multilayers. This work was supported by COLCIENCIAS project 11060511458 CT0462002 and US DOEBES. [Preview Abstract] 

R1.00138: Test of transitionstate theory for magnetic switching rates Pieter Visscher, Shuxia Wang, Dmytro Apalkov The computation of magnetic switching rates is very important in magneticrecording applications. Such rates were first computed for singledomain ferromagnetic particles by Brown[1] using an adaptation of the Kramers theory of chemical reaction rates. The simplest approximation is the socalled transitionstate theory (TST), in which one computes the rate of potentialenergybarrier crossing in an ensemble of systems that all start in one potential well by assuming it is the same as it would be in complete thermal equilibrium. In chemical reaction rate theory, this works well in many cases (when the dissipation is not very large or very small). This approximation has frequently been used in magnetic switching rate problems, where it leads to the ArrheniusNeel reaction rate formula [$\propto \exp(E_{barrier}/kT)$]. Brown (in 1963) could of course not check the result against LandauLifshitz simulation  in the present work we perform such a check. We find that if one is careful how one defines the switching rate (to avoid counting a trajectory that crosses the barrier but immediately crosses back as a switch) the TST is a very good approximation in most practical cases.\\[4pt] [1] W. F. Brown, Phys. Rev. \textbf{130}, 1677 (1963). [Preview Abstract] 

R1.00139: Anisotropy and reorientation of magnetization in magnetic Ni films Wenli Guo, Duoliang Lin A microscopic theory valid in the whole temperature range of interest and applicable to both ``Fetype'' and ``Nitype'' systems is developed to calculate the perpendicular spontaneous magnetization and various anisotropies of Ni films. The Hamiltonian is based on the Heisenberg model with the surface anisotropy, interface anisotropy, volume anisotropy and demagnetization included, in which the positive volume anisotropy is vital. The temperature and thickness dependence of various anisotropies as well as the thickness range for perpendicular remanence in magnetic Ni films are investigated by means of the Green function technique. The thicknessdriven magnetization reorientation transition is found and two critical thickness for switching on and off the perpendicular magnetization in Ni films are obtained, in qualitative agreement with experiments. Furthermore, we find that the critical thickness is almost independent of temperature. [Preview Abstract] 

R1.00140: OneMagnon and TwoMagnon Light Scattering in NiF$_2$ E. Meloche, M. G. Cottam, D. J. Lockwood, V. Gnezdilov New experimental and theoretical results concerning the temperature dependence and polarization dependence of spin waves in the canted antiferromagnet NiF$_2$ ($T_N=73 K$) are reported. In NiF$_2$ the $S=1$ singleion anisotropy favors alignment of the spins in the $ab$ plane rather than the $c$ axis and leads to a spin canting. The spin wave spectrum is obtained using a Green's function formalism where we treat the exchange terms within the RPA, while the singleion anisotropy terms are treated exactly. This theoretical approach modifies the canting angle and has a large effect on the lower frequency branch which is extremely sensitive to the choice of anisotropy parameter. The upper branch is similar to that of other rutile antiferromagnets such as FeF$_2$ and MnF$_2$. A comparison between theory and experiment for the frequency of the one magnon branches shows good agreement for temperatures up to 0.3 $T_N$. At higher temperatures various relaxation mechanisms become important. For the twomagnon light scattering we employ an interacting spinwave theory to analyse lineshapes, peak frequencies and integrated intensities in the different polarizations and compare results with our previous work on CoF$_2$ [1]. Results are deduced for the relative values of the magnetooptical coupling coefficients of NiF$_2$. [1] E. Meloche, M. G. Cottam, D. J. Lockwood, J. Magn. Magn. Mater. {272} (2004) 275. [Preview Abstract] 

R1.00141: The Magnetic and Transport Properties of MxMnO2.yH2O with the alphaMnO2type structure DerChung Yan, C. C. Chi, HsiaoYun Lin, HorngYi Tang, M. K. Wu The $\alpha $MnO$_{2}$, also called Hollandite, is an interesting material because it has 0.46 nm pore in its crystal structure, forming a onedimensional tunnel. A series of $\alpha $MnO$_{2}$ samples with different counter ions in the tunnel were synthesized. The magnetic properties show the superparamagnetic transition for all samples. The blocking temperature depends on the ionic size of counter ions and grain size. The powdery sample with K$^{+}$ as main cations in the tunnel shows anomaly with an apparent upturn below the blocking temperature. In addition, the ZFC susceptibility is larger than the FC susceptibility. We explain the upturn by the suppressing of anisotropy at the bottleneck. The temperature dependence of resistivity of the K$_{x}$MnO$_{2}$ bulks with being sintered follows the general variable range hopping formula. The magnetoresistivity of the bulk sintered at 250\r{ }C is consistent with the prediction of threedimensional variable range hopping with Coulomb gap. On the other hand, for the bulk sintered at 350\r{ }C, the exponent in the general variable range hopping formula is nearly independent of magnetic fields up to 7 Tesla. [Preview Abstract] 

R1.00142: A Study on the Magnetic Ordering in Fe$_{3}$Al and (Fe$_{0.7}$Ni$_{0.3}$)$_{3}$Al Alloy Films S. Y. Park, K. H. Han, K. H. Cho, P. J. Kim, Y. P. Lee, K. W. Kim The magnetic ordering in Fe$_{3}$Al and (Fe$_{0.7}$Ni$_{0.3}$)$_ {3}$Al films were investigated by Brillouin light scattering (BLS), and compared with the results using a superconducting quantum interference device (SQUID). (Fe$_{0.7}$Ni$_{0.3}$)$_{3} $Al and Fe$_{3}$Al films (100 nm thick) were deposited at room temperature and 400$^{\circ}$C on Si(100) substrates by ultrahighvacuum dc magnetron cosputtering. The crystal structures were understood by xray diffraction in glancing incidence mode. In order to obtain the values of the $g$factor, the saturated magnetization and the spinwave stiffness constant, the BLS experiments were employed. The temperature dependence of magnetization was measured at 5  150 K in an applied field of 3 kOe by using the SQUID. It was found that the magnetic ordering in the (Fe$_{0.7}$Ni$_{0.3}$)$_{3}$Al film, based on both the SQUID and the BLS measurements, are weaker than the Fe$_{3}$Al film. [Preview Abstract] 

R1.00143: Study on Mesoscopic Lattices of Magnetic Fluid Thin Film Subjected to Perpendicular Fields IMin Jiang, C.C. Shih, C.Y. Wang, C.K. Lu, D.J. Jang Applying a magnetic field on the magnetic fluid thin film vertically, leads a phase separation that is concentrated in particles separating from a dilute phase. The concentrated phase forms cylindrical columns that construct twodimensional lattices. This kind of artificial lattices is a novel mesoscopic system and has been explored with optical microscope, CCD, and digital imaging analysis. The twodimensional lattices present hexagonal phase with exotic topological defects due to distortion of the structure under excitation. We explore the melting evolution of the lattice by varying the applied field. The ordering of these extraordinary lattices is analyzed in terms of translational and bondorientation correlation functions to address the twodimensional melting. [Preview Abstract] 

R1.00144: Neutron scattering investigation of the magnetic correlations in Sr$_2$CoO$_3$Cl and Sr$_3$Co$_2$O$_5$Cl$_2$ Christopher Knee, Marianne Field, Robert Hughes, Mark Weller, Alexander Zhukov, Peter de Groot The magnetic interactions in the layered cobalt (III) oxychlorides, Sr$_{2}$CoO$_{3}$Cl and Sr$_{3}$Co$_{2}$O$_{5}$Cl$_{2}$, have been studied using constant wavelength neutron powder diffraction and inelastic timeofflight neutron scattering. The materials crystallize with RuddlesdenPopper structures and contain layers of CoO$_{5}$ pyramids that form CoO$_{2}$ sheets in the \textit{ab}plane separated along $c$ by SrCl rocksalt layers. The phases display contrasting magnetic properties despite the probable presence of high spin Co$^{3+}$ (S = 2) in both compounds. Sr$_{2}$CoO$_{3}$Cl undergoes a transition to long range 3D antiferromagnetic (AFM) order at a T$_{N}$ = 330 K, preceded by strong diffuse scattering from 2D spin coherence. Sr$_{3}$Co$_{2}$O$_{5}$Cl$_{2}$ does not exhibit the expected long range ordered AFM ground state, and instead the spin correlation is limited to short range 2D interactions. The material's magnetism is rationalized based on competing FM and AFM coupling. [Preview Abstract] 

R1.00145: Low temperature magnetic properties of TbRhIn5 intermetallic compound R. LoraSerrano, C. Giles, E. Granado, O. Aguero, I. Torriani, P.G. Pagliuso The low temperature magnetic properties of a new intermetallic compound TbRhIn$_{5 }$were investigated by means of magnetic susceptibility, electrical resistivity, heatcapacity and magnetic xray diffraction measurements. This compound crystallizes in a HoCoGa$_{5}$type tetragonal structure and orders antiferromagnetically at T$_{N}\sim $48 K. The xray resonant diffraction data below T$_{N}$ reveal an antiferromagnetic structure with wave vector ($\raise.5ex\hbox{$\scriptstyle 1$}\kern.1em/ \kern.15em\lower.25ex\hbox{$\scriptstyle 2$} $ $\raise.5ex\hbox{$\scriptstyle 1$}\kern.1em/ \kern.15em\lower.25ex\hbox{$\scriptstyle 2$} $ $\raise.5ex\hbox{$\scriptstyle 1$}\kern.1em/ \kern.15em\lower.25ex\hbox{$\scriptstyle 2$} $ ) and the Tb moments are aligned along the $c$axis. The temperature dependence of order parameter indicates reduced dimensionality and the magnetic properties of this compound are confronted to the properties of the other RRhIn$_{5}$ (R = rare earth). [Preview Abstract] 

R1.00146: Size effects on superconductivity and Kondo behavior in CeCo2 Y.Y. Chen, M.N. Ou, B.J. Chen, C.B. Tsai, S.J. Tsai Size effects on superconductivity and Kondo behavior were studied on a series of CeCo$_{2}$ nanoparticles (5.824 nm) by heat capacity measurements at T=0.430 K and H=08 T. In contrast to bulk CeCo$_{2}$ superconductor ($T_{C}\sim $1.3 K), no superconductivity instead an enhancement of Kondo anomaly with $T_{K }$= 1.68.8 K was revealed. Anderson's criterion can't explain the results, especially for $d \quad \ge $ 11 nm. To answer the problem the competition between Kondo interactions and superconductivity was proposed. In addition, the size dependence of $T_{K}$ and its correlation with lattice constant were observed. [Preview Abstract] 

R1.00147: Size and alloying effects on magnetic interactions in CePt2+x Y.Y. Chen, P.H. Huang, C.T. Chen, P.C. Lee, J.M. Lawrence, C.H. Booth Alloying and size effects on magnetic correlations and Kondo interactions were investigated in CePt$_{2+x}$ (x= 01). magnetic and specific confirmed that Ce in CePt$_{2}$ bulk are entire magnetic Ce$^{3+}$, but only 0.95 and 0.93 mole$^{ }$in CePt$_{2.5 }$and CePt$_{3 }$respectively. Alloying not only suppresses magnetic correlations but also enhances the quantity of Ce$^{3+}$ in Kondo interactions from 0.6 to 0.9 mole as x rises from 0 to 1. A decrease of T$_{K}$ with Pt alloying was revealed as well. Similar consequences with size reduction were also discovered, disorders created from alloying and size reduction are conjectured to be the origin of these consequences. [Preview Abstract] 

R1.00148: SpinHamiltonian for the Quantum Hall State in a Ladder Geometry Eliot Kapit, Prashant Luitel, Darrell Schroeter The first calculation of the true ground state of the parentHamiltonian proposed by Laughlin [R. B. Laughlin, Ann. Phys. \textbf{191}, 163 (1989)] for the $m=2$ Fractional Quantum Hall state on a torus is presented. Laughlin's model is generalized to the case of a system in a ladder geometry and rewritten in terms of familiar spinspin interactions, demonstrating that the model corresponds to a longrange Heisenberg Hamiltonian with an additional foursite interaction. The exact diagonalization of the Hamiltonian is performed to extract the energy, correlation functions, sublattice magnetization, and overlap with the Quantum Hall state. Our results confirm the recent work showing that the model is not exact [D. F. Schroeter, Ann. Phys. \textbf{310}, 155 (2004)] and also show it to be not without merit: the overlap between the QH state and exact ground state approaches the significant value of $0.83$ in the limit that the ladder becomes infinitely long. [Preview Abstract] 

R1.00149: The effect of inplane magnetic field on the spin Hall effect in RashbaDresselhaus system MingChe Chang In a twodimensional electron gas with Rashba and Dresselhaus spinorbit couplings, there are two spinsplit energy surfaces connected with a degenerate point. Both the energy surfaces and the topology of the Fermi surfaces can be varied by an inplane magnetic field. We find that, if the chemical potential falls between the bottom of the upper band and the degenerate point, then simply by changing the direction of the magnetic field, the magnitude of the spin Hall conductivity can be varied by about 100 percent. Once the chemical potential is above the degenerate point, the spin Hall conductivity becomes the constant $e/8\pi$, independent of the magnitude and direction of the magnetic field. In addition, we find that the inplane magnetic field exerts no influence on the charge Hall conductivity. [Preview Abstract] 

R1.00150: Bandfilling Effects on the modified Periodic Anderson Model Igor Kogoutiouk, Hanna Terletska, Eric Raymer In this research, the thermodynamical properties of the modified periodic Anderson model are investigated. Halffilled symmetrical, halffilled asymmetrical and nonhalffilled asymmetrical cases are considered. Using the equation of motion method, we found that the energy spectrum can contain one, three, four or five subbands, depending upon the parameters of the hamiltonian. The dependence of the density of states and specific heat upon the bandfilling, temperature and applied pressure is studied. It is shown that change in these parameters can lead to metalinsulator transition and/or to the change of effective mass and type of conductivity. A comparison with the previous theoretical research and experimental data is provided. [Preview Abstract] 

R1.00151: Fate of Uniform Ferromagnetism under Spin Current: Domain Nucleation Junya Shibata, Gen Tatara, Hiroshi Kohno, Yoshichika Otani A key mechanism of the currentinduced magnetization dynamics is the spin torque from a spin polarized current (spin current), which is exerted on spatial gradient of magnetization. Recently, it has been pointed out that a large spin current applied to a uniform ferromagnet leads to a spin wave instability. In this work, we show that such instability is absent in a state containing a domain wall by evaluating the spinwave dispersion around it. This may indicate that nucleation of magnetic domains occurs above a certain critical spin current. This scenario is supported by an explicit energy comparison between the uniformly magnetized state and the domainwall state under spin current. [Preview Abstract] 

R1.00152: Resonant spinHall effect in Rashba and Dresselhaus systems Bao Yunjuan, Shen Shunqing In this letter, the resonant spinHall effect is researched in 2dimensional electron gases with Rashbatype and Dressellhaustype spinorbit coupling in the presence of a strong perpendicular magnetic field and a weak inplane electric field. The calculation is focused on the Rashba system using the Kubolinearresponse theory. SpinHall conductance is found to diverge at a unique magnetic field for weak electric fields and low temperatures. The divergence comes from the interference of the two crossing Landau levels near Fermi surfaces induced by the competition between Zeeman splitting and Rashba coupling. At the resonant point, the nonlinearresponse theory is used to deal with the temperature and electric field dependence. At low temperature, the resonant spinHall current increases with the electric field and approaches to a constant and accordingly the conductance diverges as 1/$E$. For finite electric fields, the height of the peak is shown to diverge as 1/$T$ and the weight as ln$T$. In contrary, the Dresselhaus coupling enhances the Zeeman splitting and thus suppresses the resonance. The situation of both couplings coexisting is discussed based on the perturbation method. The spinHall conductance is demonstrated for different ratios of the Rashba coupling and Dresselhaus coupling. It is displayed that the peak retains when the Rashba coupling dominates and the peak height decreases with the ratio minishing. [Preview Abstract] 

R1.00153: Field induced fluctuations in percolation in granularheterogeneous LaAgMnO/ MnO Ning Zhang, G. Srinivasan Several materials in the granular form, such as transition metals and manganese perovskites, show a giant magnetoresistance (GMR) that is attributed to field induced percolation effects [1]. We discuss here the observation of GMR in the solid solution La$_{1x}$Ag$_{x}$MnO$_{3}$ (x = 0.05  0.50), possibly due to magnetic field induced fluctuation in percolation (MFP). Samples with x in steps of 0.05 were fabricated by the solgel method. We found Ag disassociation and runoff when the sample sintering temperature exceeded 800${^\circ}$, resulting in a composite of LaAgMnO and manganese oxide. Analysis of x=0.35, for example, revealed a composite composition of (La$_{0.926}$Ag$_{0.074}$MnO$_{3})_{0.698}$(MnO$_{2})_{0..302}$. Studies on such samples showed GMR that could be attributed to fieldinduced enhancement in percolation [1]. [1] Ning Zhang, Weiping Ding, and Wei Zhong et al., Phys Rev B 56, 8139 (1997). Work supported by the National Science Foundation (DMR0302254) [Preview Abstract] 

R1.00154: PES and MCD Study of Giant Magnetoresistive Spinel Compounds: Fe$_{1x}$Cu$_{x}$Cr$_{2}$S$_{4}$ (0$\leq$x$\leq$0.5) S.W. Han, J.S. Kang, S.C. Wi, S.S. Lee, G. Kim, S.J. Kim, C.S. Kim, J.Y. Kim, B.G. Park, J.H. Park, H.J. Song, H.J. Shin, K.H. Kim, J.I. Jeong Very large negative magnetoresistance (MR) and the metal insulator (MI) transition have been observed in Fe$_{1x} $Cu$_x$Cr$_2$S$_4$ (x=0, 0.5) spinel compounds.The valence states of transitionmetal (T) ions in Fe$_{1x}$Cu$_x$Cr$_2 $S$_4$ (FCCS) have been controversial. In this study, we have investigated the electronic structures and the local magnetic moments of FCCS (x=0.1, 0.2, 0.3, 0.5) polycrystalline samples by employing photoemission spectroscopy (PES), soft xray absorption spectroscopy (XAS), and magnetic circular dichroism (MCD). From the measured T 2p XAS spectra (T=Fe, Cr, Cu), the valence states of Fe, Cr, and Cu ions in FCCS have been determined. Then in the valenceband PES spectra, the Cr 3d and Fe 3d spectral distributions have been separated from other valenceelectron emissions. In the Cr 2p, Fe 2p, and Cu 2p MCD measurments, the polarities and individual magnetic moments of the Cr, Fe, and Cu ions have been determined. Based on these experiments, we will discuss on the valence states, the electronic structures, and the magnetic moments of FCCS (x=0.1, 0.2, 0.3, 0.5). [Preview Abstract] 

R1.00155: Optically induced spin polarization of an electric current through a quantum dot Anatoly Smirnov, Lev Mourokh We examine electron transport through semiconductor quantum dot subject to a continuous circularly polarized optical irradiation resonant to the electron  heavy hole transition. Electrons having certain spin polarization experience Rabi oscillation and their energy levels are shifted by the Rabi frequency. Correspondingly, the equilibrium chemical potential of the leads and the leadtolead bias voltage can be adjusted so only electrons with spinup polarization or only electrons with spin down polarization contribute to the current. The temperature dependence of the spin polarization of the current is also discussed. [Preview Abstract] 

R1.00156: Magnetotransport Properties of Compression Molded CrO$_2$Polyimide Composite Sanjay Mishra, Kartik Ghosh, Joe Losby, Ted Kehl, Ann Viano The conductivity and magnetotransport properties of compression molded halfmetallic CrO$_{2}$/Polyimide composites over a range of different metallic concentrations have been studied. The conductivity measurements on these composites show negative slope of resistance versus temperature. The magnetoresistance measurement indicates obvious enhancement at low temperatures. The maximum in magnetoresistance is found to be temperature and metal volume fraction dependent. Significant differences in high and low temperature magnetoresistive behavior in the composite have been observed. Thus, it is found that the polymer barrier can contribute to enhancing magnetoresistive properties of the composite. [Preview Abstract] 

R1.00157: Low temperature Scanning Tunneling Microscopy of Manganites Jacob Tosado, Tara Dhakal, Amlan Biswas Tunneling spectroscopy and surface imaging using scanning tunneling microscopy (STM) is an excellent technique for studying surface properties and has promoted the use of low temperature scanning tunneling microscopes (LTSTM). In this presentation we will discuss the use of scanning tunneling spectroscopy to understand the spatial variation of the density of states of ferromagnetic manganese oxide (manganite) thin films at different temperatures. We will first describe the LTSTM setup and show the calibration data for operation at temperatures down to 77 Kelvin. We will then discuss our preliminary data obtained on thin films of manganites. [Preview Abstract] 

R1.00158: Experimental study of geometries to characterize spindependent reflection J.A. Peters, Hong Chen, J.J. Heremans, N. Goel, S.J. Chung, M.B. Santos Spinorbit interaction in semiconductor heterostructures can lead to a spindependence of the reflection angle of carriers off a barrier. This effect can be exploited to create populations of spinpolarized carriers in ballistic mesoscopic geometries. We will describe experimental progress in developing sample geometries that can be used to characterize and utilize spindependent reflection. The geometries are fabricated by electron beam lithography on narrow gap heterostructures, InSb/InAlSb, in which spinorbit interaction is strong. The geometries consist of an injector aperture that directs the carriers predominantly towards a barrier, and a second aperture in close proximity collecting the carriers as a function of an applied perpendicular magnetic field. We report on progress in optimizing the geometries for given heterostructures, and present a comparative study between heterostructures. [Preview Abstract] 

R1.00159: Spindependent tunneling from Fe(001): Effect of resonant interface states K. D. Belashchenko, E. Y. Tsymbal Tsymbal \textit{et al.} [1] have studied the electronic structure of the oxidized Fe(001) surface and found positive spin polarization of the oxygen density of states. Here we study spindependent tunneling from clean and oxidized Fe surface through vacuum using the principallayer Green's function technique and the tightbinding LMTO basis. We found large negative spin polarization in both cases. Although the spin polarization of the oxygen DOS is positive tor the oxidized surface, the tunneling current primarily flows directly from Fe atoms. The dominating minorityspin channel is controlled by resonant surface states, which are sensitive to the detailed structure of the charge density at the interface. We also found that interface resonant states control the minorityspin tunneling conductance in epitaxial Fe/MgO/Fe tunnel junctions. As confirmed by a fullpotential LMTO calculation, the resonant interface band is very flat, and its bottom is very close to the Fermi level. As a result, the tunneling conductance is very sensitive to variations of the surface electronic structure. [1] E. Y. Tsymbal, I. I. Oleinik, and D. G. Pettifor, J. Appl. Phys. \textbf{87}, 5230 (2000). [Preview Abstract] 

R1.00160: Charge Transfer and Lattice Distortion in strained La0.7Ca0.3MnO3 and La0.8Ba0.2MnO3 Films on SrTiO3 Substrate ChunBin Wu, F.P. Yuan, X.G. Xu, Hsiung Chou Lattice mismatches between La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ (LCMO$ a$ = 3.86 Å) and La$_{0.8}$Ba$_{0.2}$MnO$_{3}$ (LBMO$ a$ = 3.89) CMR thin films and the substrate SrTiO$_{3}$ (00$l a $= 3.905 Å) induce a strong tensile strain that expands the inplane lattice and shortens the outofplane lattice of films. The magnetic transition temperature (T$_{c})$ and the metalinsulator transition temperature (T$_{MI})$ are then suppressed dramatically in LCMO films and are raised in LBMO films. The possible causes of the contrary phenomena are examined by Xray diffraction and HRXRD which indicate that the change of T$_{c}$ or T$_{MI}$ is highly possible due to the distortion in MnOMn chains, such as the bond length and angle, that induced the variation of orbital stability and the charge transfer in itinerant e$_{g}$ band. [Preview Abstract] 

R1.00161: POSTDEADLINE POSTERS 

R1.00162: Optical Storage of a dielectric ternary crystal doped with Europium Ricardo RodriguezMijangos, Raul PerezSalas, Gustavo VazquezPolo In this work we study the thermoluminescent properties of KCl(0.5):KBr(0.25)RbBr(0.25) with 0.01{\%} of Europium under ``beta'' radiation exposure. The glow curve shows lights emission for two temperature region. Around 140 and 332 Celsius degrees, wich increases with the time of exposure in both regions. Light emission of the second regionincreases linerly with the time. In each region there is a very small fading, showing that this crystal has high capacity to store optical energy as well as a possible dosimetry application. [Preview Abstract] 

R1.00163: Identification of Surface Debye Temperature of an Alkanethiol Self Assembled Monolayer on Au(111) by Low Energy Helium Diffraction Joshua West, Nicholas Camillone III, Peter Schwartz Using Low Energy Atomic Diffraction (LEAD), a nonperturbative and totally unpenetrating surface characterization technique, we have conducted measurements on the surface of self assembling monolayers (SAMs) of decanethiol on a Au(111) surface. DebyeWaller attenuation measurements were taken for substrate temperatures from 14.5~K to 110~K. For the lowest substrate temperatures, thermal DebyeWaller attenuation decreased consistent with a surface Debye temperature of about 100~K. The excellent order demonstrated by these particular data provided high resolution to six orders of the hexagonal peak (corresponding to the rt3 x rt3 thiol mesh). These data from higher order diffraction peaks allows us to more precisely measure the \underline {lateral} thermal vibration of the terminal methyl groups, which is considerably less than previously reported [Preview Abstract] 

R1.00164: Study of the critical current density of a hot pressed MgB$_2$ Chi Hsiang Hsieh, Chia Hao Chang, Chu Nan Chang, Hsu Hon Chung We report the result of the study of a hotpressed MgB$_{2}$. We found that the hotpressec(2.0GPa and 900\r{ } for 30 min.) MgB$_{2}$ has Tc $\cong $ 39K and $\Delta $T= 1.93 K. Its critical current density, J$_{c}$ increase about an order of magnitude than the untreated one. A significant improvement of the critical current density versus B was also found. The measurements of XRD and xray nearedge absorption spectra of B, O, and Mg edge show that the impurity of MgO originally existed in the MgB$_{2}$ powder before hot press disappears and instead B$_{2}$O$_{3}$ and other unknown impurities of compounds and oxides appear in the sample. Our result suggests that MgO is not the major impurity that cause the enhancement. [Preview Abstract] 

R1.00165: Dependence of the Superconducting Transition Temperature on Magnetization Orientation in an F/S/F Heterostructure Ion Moraru, Norman Birge It is known that placing a ferromagnet (F) in contact with a thin superconductor (S) suppresses the superconducting transition temperature of the latter due to the proximity effect. It has been proposed [1,2] that in an F/S/F structure, different mutual orientation of the magnetizations of the outer ferromagnets will produce different critical temperatures. Specifically, a slightly lower Tc should result for the parallel configuration than for the antiparallel case. This has been shown experimentally [3] using a CuNi/Nb/CuNi exchangebiased spin valve, where a difference of a few mK was observed. While dilute magnetic alloys are believed to be less destructive to superconductivity, we show that comparable results can be achieved using a pure elemental ferromagnet, in a Ni/Nb/Ni spin valve. [1] L. R. Tagirov, Phys. Rev. Lett. 83, 2058 (1999). [2] A. I. Buzdin et al., Europhys. Lett. 48, 686 (1999). [3] J.Y.Gu et al, Phys. Rev. Lett. 89, 267001 (2002). [Preview Abstract] 

R1.00166: Structure of Exfoliated Titanate Nanosheets Determined by Atomic Pair Distribution Function Analysis Milen Gateshki, Valeri Petkov, SeongJu Hwang, Dae Hoon Park, Yang Ren Titanate nanosheets find useful applications as precursors of nanocomposite materials. Colloidal suspension of titanate nanosheets has been prepared by exfoliation of Cs$_{0.67}$Ti$_{1.83}$O$_{4}$ through the intercalation of tetrabutylammonium (TBA). The atomic scale structure of the nanosheets has been determined using Xray diffraction and the atomic pair distribution function (PDF) technique, which is known to be well suited for materials showing limited structural coherence. The exfoliated titanate nanosheets have been found to be an irregular assembly of double layers of TiO$_{6}$ octahedra accommodating water and TBA molecules in the interlayer space. M. Gateshki, S.J. Hwang, D. H. Park, Y Ren, and V. Petkov, \textit{Chem. Mater. }\textbf{2004, }$16, $51535157. [Preview Abstract] 

R1.00167: Spectral Dimension of a Percolation Network Jayanta Rudra, Fozoh Saliki While the \textit{fractal dimension} $d_{f}$ describes the selfsimilar \textit{static} nature of the lattice, the \textit{spectral dimension} $d_{s}$ dictates the \textit{dynamic} properties on it. Alexander and Orbach$^{1}$ conjectured that the spectral dimension might be exactly 4/3 for percolation networks with embedding \textit{euclidian dimension} $d_{e }\ge $ 2. Recent numerical simulations$^{2}$, however, could not decisively prove or disprove this conjecture, although there are other indirect evidences that it is true. We believe that the failure of the simulations to decisively check the validity of the conjecture is due to the nonstochastic nature of the methods. Most of these simulations are Monte Carlo Methods based on a randomwalk model and, in spite of very large number of walks on huge lattices, the results do not reach the satisfactory level. In this work we apply a stochastic approach$^{3}$ to determine the spectral dimension of percolation network for $d_{e }\ge $ 2 and check the validity of the AlexanderOrbachconjecture. Due to its stochastic nature this method is numerically superior and more accurate than the conventional Monte Carlo simulations. References: 1. S. Alexander and R. Orbach, J. Phys. Lett. (Paris) 43 (1982) L625. 2. N. Pitsianis, G. Bleris and P. Argyrakis, Phys. Rev. B 39 (1989) 7097. 3. J. Rudra and J. Kozak, Phys. Lett A 151 (1990) 429. [Preview Abstract] 

R1.00168: 2Dimentional Islanding and Sublimation of Dodecane on a Au(111) Surface: An Investigation using Helium Atom Reflectivity Timothy Arlen, Craig Webster, Peter Schwartz Dodecane is deposited at submonolayer coverages onto a Au(111) surface, and the 2dimensional gas crystallizes into islands, which can again sublimate to a 2dimensional gas at higher substrate temperatures. We observe island formation and subsequent sublimation, using low energy helium reflectivity. When the dodecane molecules are deposited onto the gold surface, the specular intensity decreases as a result of loss of surface order, but recovers when the formation of dodecane islands leaves large empty surfaces of gold. The islanding process was observed in real time using specularity data for substrate temperatures of 40400 K. Two sets of specularity data were obtained: 1) Specular recovery curves following the deposition of dodecane on the Au(111) surface recorded the islanding process as a function of time, and 2) Equilibrium specular intensity was recorded as a function of substrate temperature (heating/cooling curves). A computer model of the dynamics of the submonolayer growth process using Monte Carlo simulations was developed, showing excellent agreement with experimental data of dodecane on the gold substrate. The simulations reveal insights regarding the intermolecular potential and corrugation potential of the molecules on the gold surface. [Preview Abstract] 

R1.00169: The divergence representation of the exact stress force: Implications for densityfunctional theory Ilya Tokatly We prove that the local stress force in a quantum manybody system is representable in a form of a divergence of a symmetric second rank tensor, provided that the interparticle interaction satisfies the Newton's third law. The above divergence theorem allows to formulate the exact local constraints on the exchangecorrelation potentials both in the static and in timedependent density functional theory. We show that the well known zeroforce and zerotorque sum rules represent a particular consequence of our new local condition. [Preview Abstract] 

R1.00170: Experimental Cluster State Quantum Computation Philip Walther, Kevin Resch, Terry Rudolph, Emanuel Schenck, Harald Weinfurter, Vlatko Vedral, Markus Aspelmeyer, Anton Zeilinger Standard quantum computation is based on a universal set of unitary quantum logic gates which process qubits. In contrast to the standard quantum model, Raussendorf and Briegel proposed the oneway quantum computer, based on a highlyentangled cluster state, which is entirely different. We have experimentally realized fourqubit cluster states encoded into the polarization state of four photons. We fully characterize the quantum state by implementing the first experimental fourqubit quantum state tomography. Using this cluster state we demonstrate the feasibility of oneway quantum computing through a universal set of one and twoqubit operations. Finally, our implementation of Grover's search algorithm demonstrates that oneway quantum computation is ideally suited for such tasks. [Preview Abstract] 

R1.00171: Macroscopic Effects of Quantum Entanglement Caslav Brukner, Vlatko Vedral, Anton Zeilinger It is commonly believed that for the understanding of the behaviour of large, macroscopic, objects there is no need to invoke any genuine quantum entanglement  Einstein's ``spooky action at a distance.'' We show that this belief is fundamentally mistaken and that entanglement is crucial to correctly describe some macroscopic properties of solids. We demonstrate that macroscopic thermodynamical properties  such as internal energy, heat capacity or magnetic susceptibility  can detect quantum entanglement in solids in the thermodynamical limit even at moderately high temperatures. We identify the parameter regions (critical values of magnetic field and temperature) within which entanglement is witnessed by these thermodynamical quantities. Finally, we demonstrate that two different experiments performed in 1963 and in 2000 clearly and conclusively indicate that entanglement exits in macroscopic samples of Cooper Nitrate at temperatures below 5 Kelvin. We interpret our results as indicating that entanglement may play a broad generic role in macroscopic phenomena. [Preview Abstract] 

R1.00172: Evidence for Slow Structural Relaxation and Related NonEquilibrium Dynamic Effects in preilluminated Photosynthetic Reaction Centers Anthony J. Manzo, A.O. Goushcha, G.W. Scott, N.M. Berezetska, V.N. Kharkyanen The charge recombination time of photosynthetic reaction centers (RCs) increases significantly upon lengthy illumination, allowing for nonequilibrium dynamic effects (nonequilibrium structural transitions) in the proteincofactor system. Experimental verification of such effects was made by applying photoexcitation of varying duration from .1 to hundreds of seconds, resulting in repeated cycles of the charge separation and recombination within isolated RCs. The charge recombination kinetics was monitored by transient absorption spectroscopy. The kinetic curves were analyzed using the maximum entropy method for optimization of fitting results and the relaxation spectra were calculated. These spectra for RCs with both quinone acceptors active had two or more pronounced peaks in a frequency domain for short illumination times. The peaks centered at around $\sim $1 s$^{1}$ and $\sim $10 s$^{1}$ were well distinguished. With increasing actinic pulse duration, the low frequency part of the distribution broadened and shifted gradually towards still lower frequencies, reaching values smaller than 0.02 s$^{1}$ for illumination times longer than 100 s. The results strongly support the idea of illuminationcontrolled coupling of electron transfer to macromolecule conformation in photosynthetic RCs. [Preview Abstract] 

R1.00173: Effects of Particle Size and Capping Entities on Nanocluster Properties Kimberly Frey, Will Lynch, Delana Nivens Capped cadmium and zinc sulfide compounds of varying particle size have been synthesized. The particle size is determined using the Brus equation and can be varied by modification of the concentration ratios of cadmium sulfate, sodium sulfide and the capping group, all of which are prepared using aqueous solutions.~ Nuclear magnetic resonance and thermal gravimetric analysis are used to determine the amount of coverage of the nanoparticle surface by the capping molecule. Additional information about the tumbling rates of cadmium and zinc sulfide nanoparticles and the associated motion of the capping groups can be determined from linewidth studies.~ Accurate fitting of the global tumbling parameters indicate that particle size and capping entity play a significant role. [Preview Abstract] 

R1.00174: Laser Ablation and Processing of Polystyrene Film Studied with Atomic Force Microscopy and Quartz Crystal Microbalance Yingzi Hao, Omar Musaev, Nanxia Rao, Jerzy Wrobel, Daming Zhu We used atomic force microscopy and quartz crystal microbalance to study laser ablation and processing of polystyrene in ambient environment. We used a UV nitrogen laser (337 nm) for single pulse and multiple pulse treatment of polymer film covering gold film on the quartz crystal. Laser pulse energy is regulated by diaphragm. Laser pulse or series of pulses illuminated a chosen area of polystyrene film through a mask. Morphology of processed surface is analyzed by atomic force microscope. From analysis of resonance frequency of quartz crystal mass change of polymer film can be determined and morphological changes can be distinguished from material removal. [Preview Abstract] 

R1.00175: Photophysics and biological effects of photosensitized of CdSe quantum dots Jay Nadeau, Paul Cheung Certain biomolecules are able to function as electron or hole donors when conjugated to CdSe quantum dots (QDs) in aqueous solutions; this includes very common small molecules such as the DNA purine bases, the amino acid tryptophan, and the neurotransmitter dopamine. The position of the QD bandgap relative to the aqueous redox potential of the biomolecule provides a good (but not exact) method for predicting the likelihood of electron transfer. Such transfer leads to characteristic changes in the spectral properties of the nanocrystals, including quenching of steadystate photoluminescence emission and elimination of the fast component in timeresolved spectra. Such quenched QDs are ``photosensitized'' and show unique biological properties, including the ability to pass through cell membranes, including those of bacterial cells and mammalian cell nuclei. Highresolution electron microscopy suggests that the QDs cause transient openings in the membrane of 1020 nm in size, probably due to the generation of oxidative radicals by the photosensitized QDs. Cells containing these QDs show oxidative DNA damage that is not seen when nonphotosensitized QDs are injected or taken up by endocytosis. Experiments with bacteria which are able to grow in aerobic and anaerobic conditions indicates that the presence of oxygen is necessary for membrane damage and DNA toxicity. These results provide a general method for the design of photosensitizing drugs for targeted killing of specific pathogens or cell types. [Preview Abstract] 

R1.00176: Influence of Mg on the formation of CdSe selfassembled quantum dots on ZnCdMgSe barriers Maria Noemi PerezPaz, Xuecong Zhou, Hong Lu, Mohammed Sohel, Maria C. Tamargo CdSe selfassembled quantum dots (QDs) with ZnCdMgSe barriers latticematched to InP have been recently reported$^{1}$. Under constant growth conditions, the size and consequently, the photoluminescence emission of the QDs (ranging from blue to red) is controllable and reproducible by changing the CdSe deposition time. Comparison of the optical properties (PL peak position and PL intensity) between the wellknown CdSe/ZnSe QDs system and this new system, suggests chemical effects on the formation of CdSe/ZnCdMgSe QDs. In this work, we studied systematically the influence of Mg content on the optical properties of the QDs. Very small variations of Mg concentration in the nearlatticematched ZnCdMgSe barrier result in a significant shift in QDs PL peak position (170 meV for $\sim $3.3 {\%} change in Mg). We propose that Mg could act as a nucleation site in the formation of the QDs. For an equal CdSe deposition time (equal amount of material), more Mg in the ZnCdMgSe barrier originated more nucleation centers, and consequently, smaller CdSe/ZnCdMgSe QD's. $^{1}$N. M. PerezPaz, X. Zhou, M. Mu\~{n}oz, Hong Lu, M. Sohel, and M. C. Tamargo. Appl. Phys. Lett. 85, 6395 (2004). [Preview Abstract] 

R1.00177: Magnetic Field Effects in Amorphous Solids at Ultra Low Temperatures: Survey of Materials Lidiya Polukhina, Danna Rosenberg, Stefan Lugwig, Douglas Osheroff A series of recent experiment has revealed a surprising magnetic field dependence of the dielectric constant in various multicomponent glasses at low temperatures. This dependence is not predicted by the two level system model of noninteracting tunneling centers in amorphous insulators. A rigorous theoretical explanation of the observed effects requires a systematic study of different glasses in a broad parameter range. We conduct measurements using 3He immersion cell that contained 5 different materials. Dielectric properties of samples in a temperature range from 1K to 1 mK with an applied field up to 10 mT are investigated. We present the design of a 3He immersion sample cell which will enable us to examine up to 6 materials simultaneously. We plan to investigate the dielectric properties of samples in a temperature range from 1 K down to 4 mK with an applied magnetic field up to 8 Tesla and frequencies ranging from 100 Hz to 100 KHz . [Preview Abstract] 

R1.00178: Electrical Conduction at High Fields Anil Kumar Sinha The study of electrical conduction mechanism under high D.C. electric fields of the order of 10$^5$ volt/meter and above in the sheet of insulating glass of thickness 1.00mm was carried out at room temperature(22.5$^{\circ}$C) The conduction process was ohmic at low D.C. electric fields but as the field strength increased the conductivity became field dependent and at high fields it exhibited some conductivity and variation in conduction current was nonohmic. The currentvoltage(IV) characterstic showed the nonohmic behavior in sample started at an electric fields 7.5*10$^5$ volt/meter.The log Ilog V characterstic obtained two slopes in ratio 1:2(One and square) of values 1.13 and 1.74.The observed slopes in log Ilog V characterstic suggested that the space charge limited conduction was operative.The current density and running temperature ranging from 40$^{\circ}$C to 100$^{\circ}$C(log \"{a}log 1/T characterstic) at fixed voltage 1500 volt.The value of activation energy was calculated from obtained slope and which was found to be 0.231 ev, i.e. much less than 1 ev.This suggested the predominance of Electronic Conduction. [Preview Abstract] 

R1.00179: Deconfined quantum critical point of the $O(3)$ nonlinear KiSeok Kim We investigate the quantum phase transition of the $O(3)$ nonlinear $\sigma$ model without the Berry phase contribution in two spacial dimensions. Utilizing the $CP^{1}$ representation of the nonlinear $\sigma$ model, we obtain an effective action in terms of bosonic spinons with spin $1/2$ interacting via compact U(1) gauge fields. Based on the effective field theory, we find that the bosonic spinons are deconfined at the quantum critical point of the nonlinear $\sigma$ model. It is emphasized that the deconfinement of the spinons is obtained in the absence of the Berry phase contribution. This is in contrast with the previous study of Senthil et al. [Science {\bf 303}, 1490 (2004)] where the Berry phase plays a crucial role resulting in the deconfinement of the spinons. It is the reason why the deconfinement is obtained even in the absence of the Berry phase effect that the quantum critical point is described by the XY (``neutral'') fixed point, not the IXY (``charged'') fixed point. The IXY fixed point is shown to be unstable against instanton excitations resulting from the compact U(1) gauge field and the instanton excitations are proliferated. At the IXY fixed point it is the Berry phase effect that suppresses the instanton excitations, causing the deconfinement of the spinons. On the other hand, the XY fixed point is found to be stable against the instanton excitations because an effective internal charge is zero at the neutral XY fixed point. As a result the deconfinement of the spinons occurs at the quantum critical point of the $O(3)$ nonlinear $\sigma$ model in two dimensions. [Preview Abstract] 

R1.00180: Dynamical Herd Behaviors in the YenDollar Exchange Rate Kyungsik Kim, SeongMin Yoon, C. Christopher Lee We study the phase transition of dynamical herd behaviors for the yendollar exchange rate in the Japanese financial market. It is obtained that the probability distribution of returns satisfies the powerlaw behavior $P(R) \simeq R^{\alpha}$ with three different values of the scaling exponent $\alpha = 3.11$ (one time lag $\Delta t = 1$ minute), $2.81$ ($30$ minutes), and $2.29$ ($1$ hour). The crash regime in which the probability density increases with the increasing return appears in the case of $\Delta t < 30$ minutes, while it occurs no financial crash at $\Delta t > 30$ minutes. it is especially obtained that our dynamical herd behavior exhibits the phase transition at one time lag $\Delta t = 30$ minutes. [Preview Abstract] 

R1.00181: Exact Law of Live Nature Mark Azbel' Exact law of mortality dynamics is derived. The law is universal for all species, from single cell yeast to humans. The law includes no characteristics of nonstationary animal environment interactions (e.g. via metabolism) which are necessary conditions of life. Such law is specific for live systems with their homeostatic selfadjustment to environment. Its universal dynamics for all animals, with their drastically different biology, evolutionary history, and complexity, is also unique for live systemscf thermodynamics of liquids and glasses. The law which is valid for all live, and only live, systems is a life specific law of nature. Mortality is an instrument of natural selection and biological diversity. The law which is preserved in evolution of species from humans to yeast is a conservation law of selection, evolution, and biology. It implies selection of survivors which, in contrast to species specific natural selection, proceeds via universal stepwise evolutionary rungs. It demonstrates that intrinsic mortality and certain aspects of aging are disposable evolutionary byproducts, and directed genetic and/or biological changes may yield healthy and vital Methuselah lifespan. This is consistent with experiments. Yeast may provide a master key to the mechanism of universal mortality, aging, selection, evolution, and regulation of this mechanism, in all animals. Universal mechanism dominates in evolutionary unprecedented protected populations. Well known species specific mechanisms may dominate in the wild. [Preview Abstract] 

R1.00182: Lagrangian measurements in driven twodimensional turbulence. Michael Rivera, Robert Ecke Measurements obtained from driven turbulence produced in a stratified layer are reported. The turbulence produced in this apparatus is quasitwodimensional and is dominated by the existence of ``coherent structures''. In this talk, we consider the mixing and transport of scalars within such a coherent structure dominated turbulent flow. Particular emphasis is given to understanding the effect that coherent structures have on the transport of energy and anstrophy, both from scale to scale as well as from point to point. [Preview Abstract] 

R1.00183: Magnetic Properties of Ho$_{1X}$Dy$_X$Ni$_2$B$_2$C W.C. Lee We performed the magnetization measurement on Ho$_{1X}$Dy$_{X}$Ni$_{2}$B$_{2}$C single crystals (x = 0.1, 0.2, 0.3, 0.4, 0.6) with magnetic field applied perpendicular and parallel to the caxis. There exists the strong anisotropy between magnetization data for both H $\bot $ caxis and H $\parallel$ caxis at low temperatures, which is related with the crystalline electric field effect. The increase of Dy concentration affects the magnetically ordered states of HoNi$_{2}$B$_{2}$C compound and makes the phase diagram more complicated. The antiferromagnetic ordering state attributed to Dy$^{+3}$ sublattice starts to appear from a case of x = 0.2. Finally the magnetic phase diagram becomes analogous to that of DyNi$_{2}$B$_{2}$C as x is increased [Preview Abstract] 

R1.00184: Plasmoninduced magnetization of metallic nanostructures Igor Smolyaninov, Christopher Davis, Vera Smolyaninova, David Schaefer, Jill Elliott, Anatoly Zayats Plasmoninduced magnetism of nanostructured metallic samples has been studied. Magnetic force microscopy measurements show that magnetization of a nanohole array can be achieved by illumination of the structure at the wavelengths corresponding to various surface plasmon excitations. This secondorder nonlinear optical effect appears to affect propagation of light through an array of such nanoholes in a gold film as observed by spectroscopic measurements in external magnetic field. This effect can find applications in magnetooptical data storage and optical communication and computing. [Preview Abstract] 

R1.00185: Thermodynamics of highpressure H$_{2}$O phases Vladimir Tchijov, Gloria Cruz Leon, Rainer Feistel New $PVT$ EOS of ices III and V have been derived [1], as well as new isothermal EOS of ices VII and VIII. MD simulations have been carried out to calculate the densities of ices III, V and VIII as functions of pressure and temperature; the TIP4P and TIP5P models have been adopted. A scheme [2] for calculating the heat capacity of ices II, III, V, VI, and VII has been applied. Recently developed new Gibbs thermodynamic potential function of ice Ih [3] has been used to calculate the 100 K Hugoniot of ice for pressures up to 0.5 GPa; the results are in good agreement with experimental data of Stewart [4]. The validity of the existing EOS of liquid water in the metastable region at high pressures has also been investigated. The IAPWS95 Formulation was found to be the only EOS of liquid water valid in the lowtemperature metastable region both at low and at very high pressures. [1] V. Tchijov, R. Baltazar Ayala, G. Cruz Leon, O. Nagornov, J. Phys. Chem. Solids {\bf 65}, 1277 (2004). [2] V. Tchijov, J. Phys. Chem. Solids {\bf 65}, 851 (2004). [3] R. Feistel, W. Wagner, J. Mar. Res. (2005, in press). [4] S. T. Stewart, PhD Thesis, California Institute of Technology (2002). [Preview Abstract] 

R1.00186: Steady state entanglement of two atoms created by classical driving field Ozgur Cakir, Alexander A. Klyachko, Alexander S. Shumovsky The stabilization of entanglement[17] caused by action of a classical driving field in the system of twolevel atoms with the dipole interaction accompanied by spontaneous emission is discussed. An exact solution shows that the maximum amount of concurrence that can be achieved in LambDicke limit is $0.43$. Dependence of entanglement on interatomic distance and classical driving field, beyond LambDicke limit, is examined numerically. [1] \"{O}. \c{C}ak{\i}r, A. Klyachko, and A. Shumovsky, quantph/0406081 [2] R. Tana\'{s} and Z. Ficek, J. Opt. B {\bf 6}, S610 (2004); quantph/0309195. [3] S.G. Clark and A.S. Parkins, Phys. Rev. A {\bf 90}, 047905 (2003 ). [4] B. Kraus and J.I. Cirac, Phys. Rev. Lett. {\bf 92}, 013602 (2004) . [5] S. Nicolosi, A. Napoli, A. Messina, F. Petruccione, Phys. Rev. A {\bf 70}, 022511 (2004). [6] J.B. Xu and S.B. Li, quantph/0401010. [7] M.A. Can, \"{O}. \c{C}ak{\i}r, A.A. Klyachko, and A.S. Shumovsky, Phys. Rev. A {\bf 68}, 022305 (2003). [Preview Abstract] 

R1.00187: Onedimensional photonic bandgaps in a superconductor/dielectric superlattice C.J. Wu, C.C. Liu, T.J. Yang Photonic bandgaps for a superconducting/dielectric periodic layered structure are illustrated from the transmittance spectrum that is calculated based on the Abeles theory for the stratified medium and the twofluid model for superconductors. The result shows a threebandgap structure. The first band and low frequency band gap are consistent with those predicted according to the transfer matrix method along with the Bloch theorem. The second and third bands as well as the bandgaps however can not be seen from the Bloch wave solution. The low frequency gap is shown to decrease apparently with increasing the London penetration depth, whereas the other two bandgaps are not sensitive to penetration depth. We also discuss the bandgaps as a function of the incidence angle. [Preview Abstract] 

R1.00188: Magnetic fieldtuned superconductorinsulator transition in amorphous $Nb_xSi_{1x}$ Herve Aubin, Alexandre Pourret, Kamran Behnia, Jerome Lesueur, Claire MarracheKikuchi, Laurent Berge, Louis Dumoulin New results from a study of amorphous superconducting $Nb_xSi_{1x}$ thin films will be presented. This system is observed to undergo a superconductormetalinsulator transition with variations of : Nb concentration, film thickness or magnetic field. On the superconducting compound with x=0.15, the superconducting transition temperature is observed to increase with the film thickness d, (Tc=550mK for d=1000\AA; Tc=250mK for d=125\AA), and, for each sample, a magneticfield tuned superconductorinsulator transition is observed. The field tuned transition is characterized by an isobestic point (Bc,Rc) in the magnetic field variation of the magnetoresistance, plotted for various temperatures, that indicate the quantum critical nature of this superconductorinsulator transition and the absence of an intermediate metallic state. We carefully followed the temperature dependance of this critical point (Bc,Rc) and show that the critical field value (Bc) goes down to zero at a temperature scale (1K) well above Tc for every sample studied. This analysis allows us to identify a large region in the diagram (H,T) where exists superconducting fluctuations. [Preview Abstract] 

R1.00189: Otoacoustic emissions from the cochlea as a convenient model for investigation of convectively unstable nonlinear systems David Mills Two tones introduced into the ear canal result in acoustic emissions at distortion product frequencies. Evidence suggests that the nonlinearity responsible for these distortion product otoacoustic emissions is the saturating response of hair cell transducer channels. Emissions from the normal mammalian cochlea are particularly strong and can be detected at very low sound levels. This, and other evidence, suggests the existence in mammals of a ``cochlear amplifier'' involving physical amplification of the traveling wave/basilar membrane motion driving hair cell transduction channels. A feedback or feedforward process equivalent to a convective instability seems required. The nonlinearity is essential in limiting amplification at high sound levels, thereby providing necessary range compression. Analysis focuses on observed inputoutput, or ``growth,'' functions, defined by the measurement of the amplitude of emission components as a function of varying stimulus levels with fixed stimulus frequencies. Typical growth functions demonstrate the complexity of the response, and restrict potential models of the system. [Preview Abstract] 

R1.00190: Generation of longliving entanglement between two atoms passing by a microsphere Ozgur Cakir, Ho T. Dung, DirkGunnar Welsch, Ludwig Knoll A scheme for deterministic generation of longliving maximally entangled states between two spatially well separated atoms is proposed[1,2]. In the scheme, $\Lambda$type atoms pass a resonatorlike equipment of dispersing and absorbing macroscopic bodies giving rise to bodyassisted electromagnetic field resonances of welldefined heights and widths. Strong atomfield coupling is combined with weak atomfield coupling to realize entanglement transfer from the dipoleallowed transitions to the dipoleforbidden transitions, thereby the entanglement being preserved when the atoms depart from the bodies and from each other. The theory is applied to the case of the atoms passing by a microsphere[3,4]. [1] {\"O. \c{C}ak\i r, H.T. Dung, D.G. Welsch, L. Kn\"oll, {\it quantph/0410033} } [2] {M.A. Can, \"{O}. \c{C}ak{\i}r, A. Klyachko, and A. Shumovsky, Phys. Rev. A {\bf 68}, 022305 (2003). } [3] L. Kn\"{o}ll, S. Scheel, and D.G. Welsch, in {\it Coherence and Statistics of Photons}, ed. J. Perina (Wiley, New York, 2001), p. 1 (for an update, see {\it quantph/0003121}). [4] Ho Trung Dung, S. Scheel, D.G. Welsch, and L. Kn\"{o}ll, J. Opt B: Quantum Semiclass. Opt. {\bf 4}, 169 (2002). [Preview Abstract] 

R1.00191: Modeling study the mechanism of DNA repair by the photolyase proteins Karl James Jalkanen A modeling study of the mechanism of DNA repair by the photolyase proteins has been initiated. The effects of the environment on the efficiency of the repair process have been investigated. The hybrid Becke 3LYP exchange correlation functional within density functional theory has been used to model the system. The damaged species we have modeled are the cyclobutane thymine dimer, the oxetane thymine dimer and the 6,4photoproduct (connected by only a single bond). The effects of reduction of the three damaged species and the undamaged DNA species has been investigated. For the two ring structures, reduction induces a barrierless ring opening. This supports the previously proposed model which hypothesizes that the photoreduced flavin cofactor transfers an electron (reduces) to the damaged DNA bases and with the help of the protein environment, induces the photorectivation repair process. We propose the combined use of VA, VCD, Raman and ROA spectroscopies to experimentally probe these structural changes in the DNA, the protein and the environment [1]. [1] W.G. Han, K.J. Jalkanen, M. Elstner and S. Suhai, J. Phys. Chem. B 102 (1998) 2587. [Preview Abstract] 

R1.00192: Molecular Weight Distribution Effect on MicrophaseSeparated Structures from Block Copolymers Atsushi Noro, Donghyun Cho, Atsushi Takano, Yushu Matsushita The effect of molecular weight distribution on microphaseseparated structures for both AB diblock and BAB triblock copolymers was investigated. Monodisperse three poly(styrene$b$2vinylpyridine) (SP) and poly(2vinylpyridine$b$styrene$b$2vinylpyridine) (PSP) parent block copolymers each with composition of almost 0.5 were synthesized by living anionic polymerizations They were blended variously with keeping both numberaverage molecular weight and composition constant but having different molecular weight distribution. It has been found that both SP and PSP show simple lamellar structures when molecular weight distribution is relatively wide and that domain spacing increases with increase in molecular weight distribution. Furthermore the increment of domain spacing with molecular weight distribution for PSP is larger than that for SP as is the case for composition distribution. It is thought that the expansion phenomena of microdomains must be caused by the common feature of chain length distribution of each block chain. [Preview Abstract] 

R1.00193: Electricfield effects on the optical spectra of carbon nanotubes Monica Pacheco, Zdenka Barticevic, Claudia Rocha, Andrea Latge The theoretical understanding of the optical properties of singlewall carbon nanotubes is an important problem to address since low energy lasers beam are being used to identify the chirality and diameter of the tubes and their electronic character. As well known, a singlewall carbon nanotube has many onedimensional subbands, leading to Van Hove singularities on the local density of states. When a carbon nanotube is under the influence of a laser beam, optical transitions are allowed between the Van Hove singularities and they can be observed experimentally in the absorption spectra. In carbon nanotubes the optical absorption is suppressed for polarization of light perpendicular to the nanotube axis, due to the depolarization effect. External magnetic and electric fields modify the energy spectrum of carbon nanotubes inducing changes on the optical phenomena at low frequencies. In this work we present results, using a tightbinding description, for the interband absorption coefficient of carbon nanotubes under a magnetic field and an additional external electrostatic potential for different light polarizations. [Preview Abstract] 

R1.00194: Experimental Investigation and Modeling of Electron Pulse Generation using Surface Plasmons Scott Irvine, Abdulhakem Elezzabi Ultrashort bursts of highenergy electrons can be used to study the intricate details of atomic/molecular events. Contemporary methods for generating ultrashort energetic electron pulses for timeresolved electron diffraction are based on electrostatic acceleration, which limits the electron pulse duration to several hundred femtoseconds. This results from the large experimental arrangements that are dominated by spacecharge effects. We investigate an innovative technique that employs surface plasmon waves launched with ultrashort laser pulses. This allows for synchronous generation and acceleration of electrons, eliminating the necessity of electrostatic grids and reducing the accelerating region to a space smaller than the excitation laser wavelength. Experimental results indicate that this alloptical method can produce 2 keV electrons using 30 fs, 0.5 mJ pulses from a Ti:Sapphire laser amplifier. The findings are compared with testparticle code, which indicates that the electrons are accelerated within 300 nm, yielding acceleration gradients in the multi GeV/m range. These findings open the doorway for a variety of experiments involving ultrashort timeresolved electron diffraction and pulsed xray generation. [Preview Abstract] 

R1.00195: DC and RF Characterization of Laser Annealed MetalGate SOI CMOS FieldEffectTransistors Ryan P. Lu, Bruce W. Offord, Jeremy Popp, Ayax D. Ramirez, Jason Rowland, Stephen D. Russell The conventional polysilicon gate in a MOSFET has been replaced by an aluminum metal gate which offers higher RF performance through the reduction of gate resistance. Pulsed excimer laser annealing of the source and drain was then used to avoid conventional furnace annealing that would melt the aluminum metal gate. CMOS field effect transistors utilizing metalgates were fabricated in SOI technology down to 0.25 micron gate lengths. The DC characteristics of devices with 10 micron gate lengths were consistently wellbehaved. The 0.25 micron devices were found to be more sensitive to the laser energy which showed up in the DC measurements in threshold voltage variations and larger leakage currents in the subthreshold characteristics. At higher laser fluences, TCAD simulations show excessive lateral diffusion, explaining the observed effects. RF results of the drawn 0.25 micron metalgate devices have an F$_{t}$ and F$_{max}$ of 25 GHz and 60 GHz, respectively. Similar devices with polysilicon gates were fabricated and characterized for comparison. RF results of the drawn 0.25 micron polysilicongate devices have an F$_{t}$ and F$_{max}$ of 34 GHz and 7 GHz, respectively.This device processing advance offers a deeply scalable technology for future ``systemonachip'' applications. [Preview Abstract] 

R1.00196: Carrier Lifetimes and Dynamics in Epitaxial Grown Fe2O3 / Cr2O3 Thin Films Measured by Femtosecond Transient Reflectivity and Absorption Alan Joly, Wayne Hess, Gang Xiong, David Laman, Joshua Williams, Scott Chambers Carrier lifetimes in semiconductors govern many of the physical properties of these materials including conductivity and photocatalytic yield. The use of layered thin films of semiconductor materials may allow the separation of charge carriers and hence increased carrier lifetimes, due to the heterojunction created at the interface between the two materials. In this study, the excited state carrier lifetimes of thin films of layered Fe$_{2}$O$_{3}$ and Cr$_{2}$O$_{3}$ grown on Sapphire substrates is measured using femtosecond transient reflectivity and absorption spectroscopy. Results from these experiments utilizing probe wavelengths between 1.5 and 2.7 eV on a variety of Fe$_{2}$O$_{3}$/Cr$_{2}$O$_{3}$ thin films show dynamics from the 100 fsec to hundreds of psec timescales. These dynamics can be interpreted in terms of excited state carrier relaxation, recombination, and trapping, possibly leading to the formation of defect states. [Preview Abstract] 

R1.00197: Electromagnetic Gravitation Jerry Montgomery, Philmore Russell Recent analysis of radio metric data from several space probes deployed by NASA indicate that they are being slowed by an anomalous constant acceleration with an average magnitude of$\approx 8\times 10^{10}m/s^2$ oriented with respect to the sun. Analysis of their slowdown, in addition to many other anomalous astrophysical phenomena indicates that a negative curvature of the spacetime continuum is produced by the electromagnetic radiation of the sun. The acceleration appears to have a close relation to the wavelength $\lambda _{\max } $at which the sun radiates most intensely. The evidence that supports our hypothesis may also provide solutions to the flat rotation curve of the galaxy, and rogue stars and planets within the galaxy. Calculations using the data concerning the four probes result in the formula $a=\hbar \frac{c^2}{\lambda _{\max } }$ which expresses a negative acceleration that is proportional to the speed of light divided by the peak wavelength, multiplied by a new constant $k$. The evidence also gives a strong indication that light, in addition to its particlewave nature, produces gravitational fieldlike characteristics through interacting with the spacetime continuum. [Preview Abstract] 

R1.00198: Relaxation of the general solution for RichardsonGaudin models Razvan Teodorescu, Igor Aleiner The algebrogeometric solution for the reduced BCS model describing small superconducting Al grains is investigated. The solution is derived using methods from the theory of integrable systems. Fluctuations of the spectrum induced by stochastic external fields are considered in the framework of random matrix theory. Incorporating the effects of these fluctuation through the averaging principle leads to a modified evolution equation, in general not integrable. Estimates for the relaxation time for the solitontype solutions of Richardson Gaudin models are computed. [Preview Abstract] 

R1.00199: Diffusion and Advection using Cellular Potts Model Debasis Dan, James Glazier The Cellular Potts Model (CPM) is a robust cell level methodology for simulation of biological tissues and morphogenesis. Standard diffusion solvers in the CPM use finite difference methods on the underlying CPM lattice. These methods have difficulty in simulating local advection in the ECM due to physiology and morphogenesis. To circumvent the problem of instabilities we simulate advectiondiffusion within the framework of CPM using offlattice finitedifference methods. We define a set of generalised fluid "cells" or particles which separate advection and diffusion from the lattice. Diffusion occurs between neighboring fluid cells by local averaging rules which approximate the Laplacian. CPM movement of the cells by spin flips handles the advection. The extension allows the CPM to model viscosity explicitly by including a relative velocity constraint on the fluid. The extended CPM correctly reproduces flow profiles of viscous fluids in cylindrical tube, during Stokes flow across a sphere and in flow in concentric cylindrical shells. We illustrate various conditions for diffusion including multiple instantaneous sources, continuous sources, moving sources and different boundary geometries and conditions to validate our approximation by comparing with analytical and established numerical solutions. [Preview Abstract] 

R1.00200: Diffraction and radiative lifetime within the theory of giant oscillator strength in exciton luminescence Gang Xiong, R.T. Williams The remarkably fast subnanosecond radiative lifetimes of excitonic recombination luminescence in some wide band gap materials such as ZnO have suggested that coherence properties are important to the observations. We consider the theory of giant oscillator strength and examine the spontaneous lifetime of exciton radiation, in which a single exciton emits radiation as a coherent array. We examine the dependence of transition rate on the size of the coherent source volume, and investigate how phase cancellation will affect the overall transition rate, both for previously investigated quantum dots and for larger volumes extending above a halfwavelength of the coupled light. Taking into account phase cancellation at offaxis directions, diffraction behavior is clearly recovered at the larger limit, where transition rate increases with increased coherence volume, but emitted light is progressively confined to the forward directions. The sizedependent exciton radiative lifetime could be potentially useful in developing new fast scintillator materials, and laser materials with low lasing threshold. [Preview Abstract] 

R1.00201: A material design for double honeycomb lattice superconductors Shinichi Shamoto According to our structural studies for double honeycomb lattice superconductors [1], their transition temperatures have been well scaled by their transfer integrals between the nearest neighbor transition metal atoms. Based on this finding, a material design for the bandwidth of a double honeycomb lattice superconductor is proposed. One of the high$T_{c}$ candidates, A$_{x}$YOCl (A; alkali metal) with narrow bandwidth, was found to be an insulator. This means that the A$_{x}$HfNCl system ($T_{c}^{ max}$=25.5 K) is close to an insulator region. Nevertheless, there remains a high possibility to find high$T_{c}$ materials in the double honeycomb lattice compounds based on our material design, since there are many compounds with the double honeycomb lattice modified from a popular CdI$_{2}$type structure. [1] For example, S. Shamoto \textit{et al}., Physica C 402 (2004) 283292. [Preview Abstract] 

R1.00202: A Desktop Cryogen Free Magnet For NMR And ESR Jeremy Good, Roger Mitchell Cryogenic Ltd. have built a miniature cryogen free magnet with 5 ppm uniformity at fields of 2.5 to 9 Tesla. The 2.5 Tesla magnet is cooled by a small 1kilowatt aircooled refrigerator to 4K without the use of liquid helium. The overall dimensions of the cryostat are 240 x 540mm. The workspace is a bore of 51mm. Recent developments in Cryogen Free technology have made it possible to achieve temperatures down to 3K without the use of liquid helium. They require only mains power and usually watercooling of the compressor that drives the mechanical refrigeration. A resistive lead goes from room temperature to the 1st stage of the cooler. The 1st stage operates close to 50K, which is well below the transition temperature of BISCO high temperature superconductors, which are used to carry the current from the 50K stage to the 4K stage. These give a heat load of 25 milliwatt on the 4K stage to which the magnet is attached. In practice this magnet can be operated with current permanently in the leads or in persistent mode. The magnet has homogeneity of 5ppm over a 10mm dsv. This magnet demonstrates that high fields can be produced and maintained easily in compact and practical fashion without recourse to liquid helium. [Preview Abstract] 

R1.00203: Viscous instabilities in flowing foams: A Cellular Potts Model approach. Soma Sanyal, James Glazier The Cellular Potts model has been succesfully used to model foam drainage as well as stress and strain in sheared foams. Here we investigate instabilities due to the flow of a single large bubble in a monodisperse flowing foam using the Cellular Potts model. As expected, above a certain threshold velocity, the large bubble moves faster than the mean flow. Our simulations reproduce recent experimental results of foam flow in a HeleShaw cell and reflect the importance of the cellular Potts model in successfully studying foam rheology. [Preview Abstract] 

R1.00204: Adaptive Design of Excitonic Absorption in BrokenSymmetry Quantum Wells Jason Thalken, Weifei Li, Stephan Haas, A.F.J. Levi Adaptive quantum design is used to identify brokensymmetry quantum well potential profiles with optical response properties superior to previous adhoc solutions. This technique performs an unbiased stochastic search of configuration space. It allows us to engineer manybody excitonic wave functions and thus provides a new methodology to efficiently develop optimized quantum confined Stark effect device structures. [Preview Abstract] 

R1.00205: Electronic properties of Ndoped and Cdoped TiO2: A firstprinciples study Jung Yup Lee, Jaewon Park, Jun Hyung Cho We present firstprinciples densityfunctional calculations for the electronic properties of both a nitrogendoped and a carbondoped anatase TiO2 crystal. The 2$p$ states originating from the N and C impurities appear in the band gap of TiO2. The interaction of these states with O 2$p$ states is very weak, resulting in a negligible change of the band gap. This result contrasts with a pervious theoretical analysis where the band gap of the Ndoped TiO2 is reduced by mixing N 2$p$ states with O 2$p$ states. Our calculated band structure and charge character of N 2$p$ states are consist with several recent experimental data of Ndoped TiO2, which showed that the visible light absorption is due to N 2$p$ states located above the valence band maximum rather than to narrowing of the band gap. [Preview Abstract] 

R1.00206: Modeling of Magnetostriction in Particulate Composite Materials Shin Franklin George Beginning with the basic elasticity and magnetostriction equations, we use a selfconsistent model to calculate the effective elastic and magnetostrictive behaviors of Nickel/epoxy and TerfenolD/glass composites. The longitudinal magnetostriction of pure polycrystalline TerfenolD is deduced from the experimental data of the composite having 60{\%} volume fraction of TerfenolD; Nickel data is taken from literature. Through numerical calculation, we have obtained the macroscopic longitudinal strains parallel to the applied magnetic field for TerfenolD/glass composites and both longitudinal and transverse strains for the Nickel/epoxy composites. Goodness of fit for both material systems shows our model is applicable up to very high volume fraction of inclusions. [Preview Abstract] 

R1.00207: The investigation of the dynamic morphology of block copolymer solutions by laser scanning confocal microscopy (LSCM) Hyunjung Lee, Wonmok Lee, Jongseung Yoon, Edwin L. Thomas Recently we applied laser scanning confocal microscopy (LSCM) for the study of block copolymer 3D morphology. Besides static measurement of microstructures (direct 3D imaging of block copolymer morphology), LSCM also enables the tracking of the fast dynamic process which has been impossible by conventional microscopic techniques such as TEM (transmission electron microscopy) or AFM (atomic force microscopy). In this study, insitu LSCM investigation of the morphology of confined photonic BCP solution was performed in conjunction with spectroscopic measurement for the first time. When a lamellar forming polystyrenebisoprene (480k360k, PS/PI) in cumene was placed between cover glasses, the continuous evaporation of the solvent induced a shear field along the radial direction (evaporation direction). As a result, the photonic lamellar BCP solution over the whole area developed a series of concentric ring pattern covering entire visible colors (blue to red). Comparison of the experimental result with theoretical calculation (transfer matrix method) revealed that this phenomenon mainly comes from the change of the orientation of BCP lamella based on the reflectivity at each region along the radius.. [Preview Abstract] 

R1.00208: Decorated Rods: Novel SelfAssembled DNA Nanoparticles for Gene Delivery Jason DeRouchey, Greg Walker, Ernst Wagner, Joachim R\"adler The complexation of linear DNA fragments with cationic diblock copolymers was studied as a model system for understanding ``bottomup'' selfassembly of nanoscopic gene delivery systems. Fluorescence correlation spectroscopy (FCS) measurements were performed on monodisperse linear DNA fragments complexed with diblock copolymers consisting of a cationic charged moiety, branched polyethyleneimine (bPEI), of 2, 10 or 25kDa, and a neutral shielding moiety, poly(ethylene glycol) (PEG, 20kDa). For 10 and 25kDa bPEIPEG diblocks, severe aggregation is observed despite the presence of the shielding PEG. By decreasing the bPEI length to 2 kDa, or conversely increasing the number of chains per DNA, controlled nanoparticle formation is observed. The resulting decorated particles are consistent with a “coreshell” particle consisting of a single DNA surrounded by a brush layer of densely packed PEG chains. Diffusion coefficients for both DNA and decorated DNA fragments were measured as a function of DNA length ranging from 75 to 1018 bp and are well described by a diffusing rod model. Decorated rod DNA nanoparticles showed high stability against both NaCl salt and bovine serum albumin and are of potential interest for gene delivery of short antisense DNA or siRNA. [Preview Abstract] 

R1.00209: Quantum shape effect on Zeeman splittings in semiconductor nanostructures Pochung Chen Controllability of spins in semiconductor nanostructures has become one of the important subject to be investigated in recent years due to the novel field of spintronics and quantum information processing. Manipulation of the spin depends crucially on fundamental spin properties such as the effective Lande gfactors or equivalently the Zeeman splitting. It is thus imperative to develop a feasible and accurate method to calculate magnetooptical properties of nanostructures. In this work we develop a general method to calculate Zeeman splittings of electrons and holes in nanostructures within the tightbinding framework. The isotropicity and the nonlinerity of Zeeman splitting can be reliably extracted. The method explicitly works within the electronhole picture instead of single particle conduction electronvalence electron picture. As as result, the method can be generalized to calculate exciton Zeeman splittings by including the electronhole Coulomb interaction. We will present the results for CdSe and CdTe nanostructures. The shape and size dependence of the Zeeman splitting will be discussed. [Preview Abstract] 

R1.00210: Bound nucleons have unique masses that govern elemental properties Eugene Pamfiloff It is known that measured binding energies associated with elements require equivalent energy to break the nuclear bond of a nucleus. Based upon the proposals contained in recent published works [1] [2] and with support from experimental highenergy data, it can be shown that a portion of listed binding energies are attributable to bound nucleons having a unique mass for every element. The figures show, relative to the hydrogen proton, that of the: a) 1.112 MeV binding energy per nucleon for 2H, 44{\%} or 0.486 MeV represents a change in mass ($\Delta $m) for the proton or neutron; b) of 5.629 MeV binding energy per nucleon for 7Li, 87{\%} or 4.890 MeV represents a change of mass for each nucleon; c) likewise, 56Fe has 8.811 MeV binding energy per nucleon and of this 92{\%} or 8.119 MeV represents a change in mass for each nucleon, and 232Th has 7.639 MeV binding energy per nucleon and of this, 90{\%} or 6.848 MeV represents a change in mass for each nucleon. This demonstrates that the nucleons of each element have unique masses. It has been shown that if three protons are removed from 82Pb the result is not 79Au; therefore, we conclude and predict that in addition to the Z number, elemental properties are determined by the unique proton and neutron masses for each element. megforce@physast.uga.edu [1] ``The Order of the Forces'', [2] ``The Geatron Nuclear Model'' [Preview Abstract] 

R1.00211: The Lattice Expansion Effect on the Electronic Structure on MgB$_{2}$ Ebru Gungor, Engin Ozdas For the metal intercalated boron phases, the electronic band structure calculations showed that both of the density of states (DOS) near the Fermi level and superconducting transition temperature (T$_{C})$ of MgB$_{2}$ are extremely sensitive to the volume of the unit cell. Especially, decrease of DOS and T$_{C}$ of the material under the pressure reveals that the intercalation of a larger cations could increase the unit cell volume, consequently enhances the DOS and the superconducting transition temperature. In this work, it was aimed to study the effect of lattice expansion on the electronic structure of MgB$_{2}$ and how the band structure, DOS and superconducting transition temperature change with the increase of cparameter in the frame of BCS theory are discussed. [Preview Abstract] 

R1.00212: Initial C incorporation on Si(111) studied by STM Dohyun Lee, Hanchul Kim, JaYong Koo We report the initial C incorporation on Si(111) by the C$_2 $H$_2$ deposition at 500 $^{ \circ}$C using scanning tunneling microscopy. We find that the thermally decomposed C atoms from C$_2$H$_2$ are incorporated into the sublayer of Si(111) surface preserving $7 \times 7$ dimeradatomstacking fault structure. C atoms are mainly incorporated into the underneath of corner adatoms of faulted halves of Si(111) surface at 500 $^{ \circ} $C. Our experimental results are compared with the previous reports of several authors regarding the Cincorporated Si(111)$\sqrt{3} \times \sqrt{3}$ superstructure induced by the higher C$_2$H$_2$ exposure at the similar substrate temperature range. [Preview Abstract] 

R1.00213: Complete Scheme for TwoQubit Quantum Computing using Pulsed ESR of $^{15}$N@C$_{60}$ Gavin W. Morley, Johan van Tol, Jinying Zhang, Mark A.G. Jones, Andrei N. Khlobystov, Kyriakos Porfyrakis, Arzhang Ardavan, G. Andrew D. Briggs $^{15}$N@C$_{60}$ is a fullerene molecule containing an atom of nitrogen15. Its long electron spin decoherence time makes it attractive for quantum computing. The electronic and nuclear spins of the nitrogen atom are good quantum numbers in a strong magnetic field, coupled by the hyperfine interaction. Pulsed electron nuclear double resonance (ENDOR) can be used to initialize, manipulate and measure this twoqubit system. We used dynamic nuclear polarization (DNP) to prepare an initial state in which the nuclear and electronic spins were aligned with the applied field. We measured this to be an 80\% pure state. The decoherence time of N@C$_{60}$, $T_2$, can be increased to 215 $\mu$s at 4 K. The electronic $T_1$ time is the relevant timescale for reading out the result of a computation. At 4.2 K this is 4.5 minutes, and the nuclear $T_1$ is greater than 12 hours. www.nanotech.org [Preview Abstract] 

R1.00214: Magnetotransport Properties of Magnetic Oxides Will Branford, Fridrik Magnus, Ying Lin Liu, Neeraj Khare, Ming Wei, Judith MacManusDriscoll, Maria Luisa Parames, Nicoleta Popovici, Ernesto Jimenez, Olinda Conde, Kelly Morrison, Yasuyuki Miyoshi, Steven Clowes, Yury Bugoslavsky, Lesley Cohen Hybrid spintronic devices require high Curie temperature ferromagnets with a large transport spin polarization. It has been predicted that efficient spin injection is facilitated by matching the conductance of the ferromagnet to that of the semiconductor and in this respect dilute magnetic semiconductors look to be more attractive for application. Oxide dilute magnetic semiconductors are the only class to date that may offer Curie Temperatures above 300K. Here we review the effect of chemical substitution and/or growth parameters on the magnetic, magnetotransport and spin polarisation of charge carriers of a range of functional ferromagnetic oxides, such as Fe$_{3}$O$_{4}$, Nd$_{2}$Mo$_{2}$O$_{7}$, Co$_{x}$Ti$_{1x}$O$_{2}$ and Co$_{x}$Zn$_{1x}$O. [Preview Abstract] 

R1.00215: AngleDispersive HighPressure Synchrotron Radiation XRay Diffraction Studies of Pentaerythritol Tetranitrate on Compression Sequence up to 30 GPa Kristina LipinskaKalita, Michael Pravica, Malcolm Nicol Highpressure synchrotron xray diffraction studies of pentaerythritol tetranitrate, C(CH$_{2}$ONO$_{2})_{4}$, have been performed \textit{insitu} (diamond anvil cell). The spectral changes at low pressures (up to 7 GPa) indicated continuous densification of the tetragonal structure (space group $P\overline 4 2_{1}c)$ and the compound compressed with a 17{\%} decrease in the unit cell volume. At 8 GPa and above several new diffraction lines appeared in the patterns. These lines have been attributed to a pressureinduced structural transformation from the tetragonal to an orthorhombic structure (space group $P2_{1}22_{1})$. The progressive broadening of the diffraction lines that appeared with pressure increase beyond 10 GPa was attributed to a blend of two coexisting PETN phases with combined diffraction lines. More detailed highpressure investigations will follow, in particular regarding the choice of the space group of the proposed new orthorhombic structure. [Preview Abstract] 

R1.00216: Synchrotron XRay Diffraction Probe of PressureInduced Phase Transition in the Nanocrystalline Phase of a GlassBased Composite Kristina E. LipinskaKalita, Patricia Kalita, Russell J. Hemley \textit{In situ} synchrotron radiation xray diffraction studies were performed on a glassceramic nanocomposite on compression up to 43 GPa and on successive decompression. The optically transparent material contained nanometersized single crystalline phase homogeneously dispersed within an isotropic host matrix. The pressureevolution of xray diffraction patterns was consistent with a phase transition occurring in the gallium oxide nanocrystals leading to a metastable phase. This work is the first report of a pressureinduced phase transition arising in the nanocrystalline phase of a glassceramic composite that involves transition form a thermodynamically stable to an unstable phase, maintained after pressure release, by the densified host glass matrix. [Preview Abstract] 

R1.00217: Fourier transform angleresolved photoemission. Volodymyr Borysenko We suggest a new spectroscopic technique, which allows to further extend the capabilities of the conventional angleresolved photoemission spectroscopy (ARPES). Recent improvement of the energy and momentum resolution in photoemission spectroscopy has been accompanied by the rapid development of the computerbased data acquisition routines. As a result, the typical measuring time has been significantly reduced. This, in turn, allows to record the photoemission intensity from the virtually complete halfspace defined by the sample surface. At the same time, the modern synchrotron radiation offers the opportunity to use higher photon energies without considerable increase of the bandwidth. Already using the 100 eV photons one can cover nearly 25 typical Brillouin zones (in a repeating zone scheme). We propose to compute a Fourier transform magnitude F (\textbf{\textit{r}}, E{\_}b) from the measured A (\textbf{\textit{k}}, E{\_}b) distribution. The physical meaning of the obtained characteristic length scale is discussed. This technique can be proven valuable because of its exceptional capability to relate the \textbf{\textit{k}}space electronic structure to that in real space. [Preview Abstract] 

R1.00218: Confined diblock copolymer melts: a fieldtheoretic computational study Alfredo AlexanderKatz, Glenn Fredrickson Using fieldtheoretic simulations, we study the effects of confinement and fluctuations in the location of the orderdisorder transition (ODT) for a diblock copolymer system. Specifically, we consider a melt of copolymers confined between two neutral hard walls separated by a distance L. For this system, it is found that confinement induces a shift in the ODT which depends on the strength of the fluctuations (dominated by the length of the copolymers), as well as on the width of the slit. The shift in the ODT due to fluctuations presents a minimum when the slit width is comparable to the unperturbed size of the polymer. Also, we present results on the structure of the disorder phase close to the ODT which exhibits nontrivial oscillations in the composition fluctuations. [Preview Abstract] 

R1.00219: Adsorption of NH$_{3}$ on Si(001) and Bi nanolines James Owen, David Bowler, Kazushi Miki Ammonia adsorbs dissociatively onto the Si(001) surface. Using scanning tunnelling microscopy(STM), we have identified the major and minor fragments that result and have found that adsorption is correlated along dimer rows. From our STM data we have determined the strength of the correlation between neighbouring adsorbates, and found that the direction of the correlation changes between 300K and 450K. We propose a reaction pathway based on the STM data and DFT modelling. The Bi nanoline is inert to adsorption of ammonia, and hence ammonia can be used to passivate the Si(001) surface. [Preview Abstract] 

R1.00220: Large Eddy Simulation and Reconstruction of Local Fluctuations for the AeroAcoustic Characterization of Ventilation Nozzles Christoph Reichl, Christian Krenn, Hermann Lang, Martin Mann Ventilation nozzles are often identified as significant aeroacoustic sources, the predominant sound generation process being due to turbulence in the shear layer of the nozzle's free jet. Different nozzle types (circular, elliptic and coaxial circular, Reynolds number 100.000) are characterized with respect to local fluctuation spectra and the acoustic far field signal using two different numerical approaches: (1) Velocity, turbulent kinetic energy and dissipation rate from steady RANS calculations are used for the reconstruction of artificial velocity fluctuation time series; (2) transient LES are performed to extract the actual time dependent turbulent velocity field. Both approaches lead to a huge quantity of data (500 GBytes per run), which is processed using Lighthill's Acoustic Analogy to gain the far field acoustic sound pressure and frequency content. Both methods have the potential of characterizing the acoustic behavior. However, local pressure fluctuations showing the typical frequencies of the vortex formation mechanism can only be extracted using unsteady CFD. [Preview Abstract] 

R1.00221: Dielectric Response of Metallic Nanoclusters Amy Cassidy, Stephan Haas, A.F.J. Levi We study the dielectric function for metallic nanoclusters. The dielectric function is calculated from the eigenstates, using a tightbinding Hamiltonian. I will present our findings on the dependence of surface plasmon frequency and oscillator strength on the system size and geometry. [Preview Abstract] 

R1.00222: Twentyfirst Century Physics Jerry W. Jensen Predictions were made prior to Huygens deployment that the density and mass of the moon Titan are much greater anticipated, and the result of this greater mass would be a very rapid if not fatal descent. These predictions were based upon nonNewtonian, nonrelativistic physics derived from cosmic, macro and micro phenomena. Confirmation of this prediction is found in the inexplicable descent profile of the Huygens probe. The scale of this effect can be confirmed through careful reexamination of the orbital and descent dynamics near Venus, Mars and Jupiter. The model of the physical world created to make this prediction contraindicates the GR solution, and is able to assign causality to many poorly understood phenomena including, but not limited to triboelectric effects, supernova expansion and the associated gamma rays, expansion 'ring's and residual radiation; AGN jets, the solar corona, the solar neutrino count, Xray emitting gases, the TullyFisher relationship, the MOND effect, turbulence, the limited turbulence observed on Jupiter, the effects of earthquakes on the ionosphere, null results of cosmic gravitational wave experiments, and a variety of cosmic redshifting factors. The exceptional voyage of the Huygens probe has ushered in a new era of physics. [Preview Abstract] 

R1.00223: Future device applications of lowdimensional carbon superlattice structures Somnath Bhattacharyya We observe superior transport properties in lowdimensional amorphous carbon (aC) and superlattice structures fabricated by a number of different techniques. Low temperature conductivity of these materials is explained using argument based on the crossover of dimensionality of weak localization and electronelectron interactions along with a change of sign of the magnetoresistance. These trends are significantly different from many other well characterized ordered or oriented carbon structures, and, show direct evidence of high correlation length, mobility and an effect of the dimensionality in lowdimensional aC films. We show routes to prepare bespoke features by tuning the phase relaxation time in order to make highspeed devices over large areas. The artificially grown multilayer superlattice structures of diamondlike amorphous carbon films show highfrequency resonance and quantum conductance suggesting sufficiently high values of phase coherence length in the present disordered aC system that could lead to fast switching multivalued logic. [Preview Abstract] 

R1.00224: Ratchet effect in an optical lattice Emil Lundh, Mats Wallin The possibility of realizing a directed current for a quantum particle in a flashing asymmetric potential is investigated. It is found that quantum resonances in the effective Planck constant give rise to a directed current. [Preview Abstract] 

R1.00225: Array for high spatial resolution multiparameter fiber optic sensing P. Henning, R.J. Olsson, A. Benko, A.W. Schwabacher, P. Geissinger A novel 10x10 fiber optic distributed sensor array has been developed, capable of both positional sensing and specialized chemical sensing. Each sensor consists of two crossed optical fibers, in which the claddings are removed and replaced by an environment that includes highly fluorescent molecules. Light is evanescently coupled from the source fiber to the material, which in turn fluoresce. The fluorescent light is detected via the sensing fiber. Since each fluorescent signal can be delayed in time by the overall length of each sensor fiber, the response of two sensors only millimeters apart are resolvable. By tailoring the aspects of each sensor for high sensitivity to a specific parameter, a variety of properties can be evaluated simultaneously, while the positional dependence of a given factor across the array can be observed. [Preview Abstract] 

R1.00226: From aperiodic nanolines to imperfect $\sqrt3\times\sqrt3$: a survey of bismuth overlayer structures on Si(001) and Si(111) Jennifer MacLeod, Alastair McLean Bismuth overlayers on silicon surfaces are of considerable interest because of their surfactant properties in epitaxial germanium growth. Careful control of bismuth deposition parameters can result in a number of different surface structures, from the irregularly spaced, onedimensional bismuth line system on Si(001) to the different phases of the $\sqrt3 \times\sqrt3$R30$^\circ$ reconstruction on the Si(111) surface. The leitmotiv underlying all of these overlayer systems is the strain generated by the mismatch between the covalent radii of bismuth and silicon; manifestations of this will be illustrated through scanning tunneling microscope (STM) images. We will explore the evolution from the 2$\times$n reconstruction on (001) to the bismuth line surface, and illustrate the largescale domain structure of the line system. A new type of defect structure on the bismuthcovered Si(111) surface will be described and examined in the context of surface strain. [Preview Abstract] 

R1.00227: Study of electronic structure and valence state of CeCo$_{2}$ nanoparticles ChungLi Dong, YangYuan Chen, ChingLin Chang, Jinghua Guo We have performed the Ce L$_{3}$, M$_{4,5}$edge and Co L$_{2,3}$, Kedge xray absorption measurements to investigate the dependence of valence state and local electronic structures on different particles size of CeCo$_{2}$. By monitoring the modifications in Ce L$_{3}$ and M$_{4,5}$edges XAS spectra shape, the individual intensities of the two valence states reflect the mixed configuration in the ground state in CeCo$_{2}$. The Ce in nanopartice CeCo$_{2}$ exhibits mixed valence with only small amount of tetravalent Ce, which is in contrast to the bulk. Combination with the results observed from the Co L$_{2,3}$, Kedge, reduced in valence for nanoparticles can be interpreted in terms of surface effects and gives rise to weaker hybridization between the Co 3d and Ce 4f5d states. [Preview Abstract] 

R1.00228: Thermodynamic properties of CdSe quantum dots S. Neeleshwar, C.L. Chen, C.B. Tsai, Y.Y. Chen, C.C. Chen We have fabricated a series of CdSe quantum dots with different size 2.8, 4.1 and 5.6 nm by solution phase method. The size effects were investigated by the measurements of magnetic susceptibility and heat capacity. The Pauli magnetic susceptibility linearly increased with surface atom fraction reflecting the appearance of surface density of states of conduction electrons. The linear coefficient of specific heat $\gamma $ for 2.8 nm is $\sim $5.5 mJ/mol K$^{2}$ which is about five times that of the bulk. The enhancement Pauli magnetic susceptibility and linear coefficient of specific heat in quantum dots gives a strong evidence of the formation of electron delocalization and the surface disorder effects. [Preview Abstract] 

R1.00229: The Electrostatic Gavimeter: An Alternative Way of Measuring Gravitational Acceleration David Kashinski, Paul Quinn In the past, Earth’s gravitational acceleration $g$ has been measured in many ways, including the use of a pendulum as well as other models involving the use of a mass and a spring. We have designed a new method incorporating a spring with a capacitor and a voltmeter. This capacitor model still uses a hanging mass on a spring, but alters the method of determining the change in position of the spring due to the gravitational acceleration. We relate the change in position to the potential difference across the capacitor needed to cause a discharge through parallel plates. By relating this voltage directly to the gravitaional acceleration,a new method of measuring $g$ is obtained. [Preview Abstract] 

R1.00230: Increasing the Size of Microwave Popcorn Justin Smoyer, Brett Fowler, Paull Quinn Each year Americans consume approximately 17 billion quarts of popcorn. Since the 1940s, microwaves have been the heating source of choice for most. By treating the popcorn mechanism as a thermodynamic system, it has been shown mathematically and experimentally that reducing the surrounding pressure of the unpopped kernels, results in an increased volume of the kernels [Quinn et al, http://xxx.lanl.gov/abs/condmat/0409434 v1 2004]. In this project an alternate method of popping with the microwave was used to further test and confirm this hypothesis. Numerous experimental trials where run to test the validity of the theory. The results show that there is a significant increase in the average kernel size as well as a reduction in the number of unpopped kernels. [Preview Abstract] 

R1.00231: The Fermi Statistics of a Weakly Excited Column of Granular Particles in a Vibrating Bed Holly Kokstein, Paul Quinn A one dimensional experiment in granular dynamics is carried
out to test the thermodynamic theory of weakly excited granular
systems [Hayakawa and Hong, Phys. Rev. Lett. 78, 2764(1997)]
where granular particles are treated as spinless Fermions. The
density profile is measured and then fit to the Fermi
distribution function, from which the global temperature of
the system, $T$, is determined. Then the center of mass, $ 

R1.00232: The Liquidsolid Transition of Two Dimensional Hard Spheres Under Gravity Using a Global Equation of State Paul Quinn, Daniel Snyder In a previous paper, Hong started with the Enskog equation of hard spheres of mass $m$ and diameter $D$ under gravity and derived an exact equation of motion for an equilibrium density profile at a temperature $T$. [D.C. Hong, Physica A, 271, 192 (1999)] This leads to a transition between the liquidand solid regimes of the granular system that is temperature dependent. In this derivation, Hong used the Ree and Hoover correlation function, which is typically for lower density systems, to obtain his results. In a previous paper, Luding obtained a global equation of state for hard spheres in two dimensions that is valid over the entire range of densities of a granular system. [Luding, Physical Review E, 63, (2001)] Using this new global equation of state as well as the ideas expressed by Hong, we obtain a more exact equation of motion for an equilibrium density profile at a temperature $T$ in two dimensions. We then explore this new equation and find that it further supports the condensation theory as presented previously by Hong. [Preview Abstract] 

R1.00233: Nonadiabatic electron transfer from conjugated polymer to semicnductor nanocrystal Svetlana Kilina, Kiril Tsemekhman, Dmitri Kilin, Oleg Prezhdo The photoinduced ultrafast electron transfer from the conjugated polymer (PolyPhenyleneVinylene) to the semiconductor nanocrystal (Titanium dioxide / Cadmium Selenide) has been analyzed with nonadiabatic molecular dynamics simulation within classical path approximation. An abinitio molecular dynamics trajectory is launched for 1ps with initial velocities rescaled to match the room temperature. Nonadiabatic couplings between polymer and semiconductor calculated at each time step are used to construct timedependent Hamiltonian that drives ellectron transfer process. The polymernanocrystalline composite appears as costefficient alternative for traditional Silicon Photovoltaic Cells. [Preview Abstract] 

R1.00234: STM, LEED and IPS study of Ag/Al(100) Jean F. Veyan, Marcos Flores, P. H\"aberle The room temperature growth of thin layers of Ag on Al(100) has been shown to be in the StranskiKrastanov mode. A different behavior is seen in this system, close to LN2 temperatures. From the coverage dependence of the inverse photoemission (IPS) intensity, we can infer an epitaxial layer by layer growth mode. This is confirmed by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) measurements. For 0.5 ML Ag coverage, the LEED pattern shows a (1x5) surface reconstruction which agrees with STM images displaying long stripe structures along the [11] direction. We attribute these structures to the formation of a surface alloy. For higher coverages, the stripe structures are still present but with a high density of dislocations, which precludes the observation of a LEED pattern between 4 and 7 ML. From 8ML and up the 1x1 LEED pattern is recovered consistent with a layer by layer growth. The interest in this system resides in the existence of quantum size effects displayed by the unoccupied electronic states in the Ag overlayer. [Preview Abstract] 

R1.00235: Quantum size effects induced by barrierless confinement Patricio H\"aberle, J. Francois Veyan We have measured the thickness dependence of Inverse Photoemission (IPS) intensity in the Ag/Al(100) system. Intensity variations show a smooth dependence as a function of coverage which is interpreted as a layer by layer growth. We have used a two step potential to model the effect of the crystal on the valence electrons at the overlayer. Calculated resonaces due to the reflection at the potential step show similar energies as those shown in the experimental data. A refinement of the model, using a corrugated potential for the Ag atoms provides a full description of the experimental coverage dispersion. [Preview Abstract] 

R1.00236: Detonation Properties Measurements for Inorganic Explosives Brent A. Morgan, Angel Lopez, Selma Goldstein, Daniel Gunter Many commonly available explosive materials have never been quantitatively or theoretically characterized in a manner suitable for use in analytical models. This includes inorganic explosive materials used in spacecraft ordnance, such as zirconium potassium perchlorate (ZPP). Lack of empirical information about these materials impedes the development of computational techniques. We have applied high fidelity measurement techniques to experimentally determine the pressure and velocity characteristics of ZPP, a previously uncharacterized explosive material. Advances in measurement technology now permit the use of very small quantities of material, thus yielding a significant reduction in the cost of conducting these experiments. An empirical determination of the explosive behavior of ZPP derived a Hugoniot for ZPP with an approximate particle velocity (u$_{o})$ of 1.0 km/s. This result compares favorably with the numerical calculations from the CHEETAH thermochemical code, which predicts u$_{o}$ of approximately 1.2 km/s under ideal conditions. [Preview Abstract] 

R1.00237: Electron Correlation and Charge Transfer in (Ba$_{0.9}$Nd$_{0.1})$CuO$_{2+\delta }$/(CaCuO$_{2})_{2 }$Superconducting Superlattices Observed with Resonant Inelastic Xray Scattering Byron Freelon Inplane CuO$_{2}$ physics of the 2$\times $2 highT$c$ superlattice (Ba$_{0.9}$Nd$_{0.1}$CuO$_{2+x})_{2}$/(CaCuO$_{2})_{2}$ was investigated by applying xray emission/absorption spectroscopy. The superlattices are fabricated by pulsedlaser molecular beam epitaxy (MBE) in a layerbylayer fashion.\footnote{G. Balestrino, S. Lavanga, P. G. Medaglia, P. Origiani, A. Paoletti, G. Pasquini, A. Tebano, and A. Tucciarone, Appl. Phys. Lett. \textbf{79}, 99 (2001).} The$_{ }$superlattices consist of two layers; an infinite layer (IL) and the charge reservoir (CR). Each insulating layer is alternately deposited to produce superlattices exhibiting a T$c$ of 80K.\footnote{G. Balestrino, P. G. Medaglia, P. Origiana, A. Tebano, C. Aruta, S. Lavanga, and A. A. Varlamov, Phys. Rev. Lett. \textbf{89,} 156402 (2002).} We measure the O 1$s$ density of states to be insulating for the component layers and metallic for the superlattice. Using resonant inelastic scattering (RIXS) we make the first direct observation of ZhangRice singlets in artificial hightemperature superconducting heteroepitaxial structures. ZhangRice singlet polarization dependent studies are performed, and the absorption and emission results are compared to localdensity approximation theory. Xray emission spectra of the superlattice and its component layers gives evidence of charge transport from the charge reservoir to the infinite layer. Cuedge resonant xray emission is performed to probe \textit{dd} excitations in the component layers and superlattice. [Preview Abstract] 

R1.00238: Phase Transitions in Bi using laser ICE J.O. Kane, R.F. Smith Experiments are underway at the Janus laser to study phase transitions in isentropically compressed Bi. The targets consist of 1435$\mu$m of Bi attached to windows of LiF or sapphire. The Bi side of the target is loaded using a ramped laser ICE drive. The velocity history of the Bi:window interface is recorded using line VISAR. The response of the targets is modeled by evolving the 1D Euler equations with an assumed pressure source on the drive side of the target. The pressure source is deduced by back integration from shots performed with Al:window targets. The Hayes threephase EOS parameters are used for the Bi. Following Hayes, we also model the III transition with rate dependence. We present results of the data and comparisons to the modeling. [Preview Abstract] 

R1.00239: Ferromagnetic behavior in Cr and Mndoped indiumtin oxide thin films John Philip, Scott Layne, Tiffany Santos, Jagadeesh Moodera Hightemperature ferromagnetism is demonstrated in Cr and Mndoped indiumtin oxide (ITO) films deposited using reactive thermal evaporation. These films were grown on sapphire (0001), Si/SiO$_2$, as well as Si(001) substrates with the highest magnetic moment observed around $\sim$1$\mu_{B}$/Mn. The electrical conduction is n type, an anomalous Hall effect was observed, showing that the carriers in this system are spin polarized. Mndoped samples were singlephase, whereas at high Cr concentrations, there was CrO$_2$ present. The carrier concentration can be varied independent of the Mn concentration in this transparent ferromagnetic semiconductor for its easy integration into magnetooptoelectronic devices. Supported by the CMI project at MIT and NSF [Preview Abstract] 

R1.00240: Device Piggy Back on Bacteria: Selective Nanoparticle Deposition on Live Bacterium Vikas Berry, Ravi Saraf Due to strong electrostatic attractive force, charge stabilized nanoparticles in solution (such as of Au), deposit and selfassemble at a faster rate on a solid substrate than particles stabilized by steric hindrance. The electrostatic interparticle repulsion between charge particles restricts the structure to a monolayer; however, the layer can not be percolating. On biological surfaces, with tethered functional biomolecules, we demonstrate fabrication of monolayers of 1030 nm Au nanoparticles that are electrically conducting over 10 $\mu $m. The contact appears to be a metal/insulator/metal junction where the insulator is `charge neutralizing' biomolecules on the bacteria surface that `grabs' the particle as it lands on the surface. By modulating the property of the `insulator' a reversible humidity sensor is designed with higher sensitivity at low humidity that is in contrast with most impedance based humiditysensors. [Preview Abstract] 

R1.00241: Simulating the LIGO Detector Dominic Dubois, Sanichiro Yoshida, Tiffany Findley, Raghuveer Dodda, Kristen Rogillio The LIGO (Laser Interferometer Gravitationalwave Observatory) detector is a Michelson Interferometer designed to detect strains of space time on the order of 10$^{19}$. Due to the low magnitude of the expected signal, the sensitivity of the instrument must be extremely high, and any disturbance to the interferometer optics must be eliminated. We are interested in simulating the effect of ground motion on the performance of the interferometer. We constructed a computer code to simulate the Input Optics, an optical subsystem between the laser source and the interferometer arm, using the E2e (endtoend) model, a simulation package developed by LIGO project, and combined it with the existing code developed by other LIGO groups to simulate the rest of the interferometer. Our recent results indicate that the motion of the Input Optics's has noticeable effect on the optical field at the signal port. More detailed analysis is under way. . [Preview Abstract] 

R1.00242: Physical and Morphological Characterization of Templated Thermosets Theresa J. HermelDavidock, H. Sean Tang, Steve F. Hahn, Dan J. Murray, Nikhil E. Verghese It has been found that by the addition of low concentrations of an amphiphilic block copolymer to an epoxy resin, novel disordered morphologies can be formed and preserved through cure. It has also been found that the addition of small amounts of block copolymer can improve the fracture resistance significantly without sacrificing the high modulus and glass transition temperature of these thermoset materials. This report will focus on characterizing the influence of the block copolymer and casting solvent on the morphology achieved in the thermoset sample and the resulting physical properties. Templated thermoset samples exhibiting two different diblock copolymer morphologies, wormlike micelles and spherical micelles were investigated. The microdeformation mechanisms of these templated thermosets were studied via an insitu tensile deformation technique performed in a transmission electron microscope (TEM). The microdeformation behaviors of these samples were found to correlate well with the macroscopic mechanical properties. The toughening effect obtained in the epoxy resin was attributed to the welldispersed wormlike morphology and the weak interfacial adhesion between the micelles and the matrix. [Preview Abstract] 

R1.00243: Ion Beam Energy Dependant Study of Nanopore Sculpting Brad Ledden, Eric Krueger, Jiali Li Experiments show that ion beams of various energies (1keV, 3keV, and 5keV) can be used to controllably ``sculpt'' nanoscale features in silicon nitride films using a feedback controlled ion beam sculpting apparatus. We report on nanopore ion beam sculpting effects that depend on inert gas ion beam energy. We show that: (1) all ion beam energies enable single nanometer control of structural dimensions in nanopores; (2) the ion beam energies above show similar ion beam flux dependence of nanopore formation; (3) the thickness of nanopores differs depending on ion beam energy. Computer simulations (with SRIM and TRIM) and an ``adatom'' surface diffusion model are employed to explain the dynamics of nanoscale dimension change by competing sputtering and surface mass transport processes induced by different ion beam irradiation. These experiments and theoretical work reveal the surface atomic transport phenomena in a quantitative way that allows the extraction of parameters such as the adatom surface diffusion coefficients and average travel distances. [Preview Abstract] 

R1.00244: Voltage and Viscosity Dependant DNA Translocation Through Solid State Nanopores James Uplinger, Brian Thomas, Daniel Fologea, Jiali Li The effects of different voltages and solution viscosities on 3 kbp double stranded DNA translocating through 2 to 12 nanometer silicon nitride nanopores are investigated. The translocation time of an event has been found to be inversely proportional to the driving voltage, and to be increased nonlinearly with increased glycerol concentration. [Preview Abstract] 

R1.00245: Magnetic State in Nanostructured ZnFe$_2$O$_4$ at Low Temperature Jeong Hyun Shim, Soonchil Lee, Jung Hye Park, S.J. Han, Y.H. Jeong, Y.W. Cho Nanostructured ZnFe$_2$O$_4$ prepared by highenergy ball milling process for 4 h, showed spontaneous magnetization below 460K,while bulk ZnFe$_2$O$_4$ has antiferromagnetic state below 10K. Magnetic state in this ballmilled ZnFe$_2$O$_4$ at low temperature was investigated by observing the behavior of spectrum of zerofield nuclear magnetic resonance with applying external magnetic field and varying temperature. In addition to verifying ferrimagnetic state that is naturally expected, we found the coexistence of antiferromagnetic long range ordered state in octahedral site. Canted state appeared only in magnetization of octahedral site that consists of the ferrimagnetic state. [Preview Abstract] 

R1.00246: Annihilation of Vortex Pairs in Submicron Permalloy Stadia Peter Eames, Hao Wang, C.E. Campbell, E. Dan Dahlberg The annihilation processes for a vortex pair in a submicron, stadium shaped permalloy particle were studied using micromagnetic simulations.~ The stadium shape, defined as a rectangle with semicircular ends, preserves much of the circular symmetry while still allowing multiple vortices to be stable at remanence. Beginning from the remanent state of a vortex pair located symmetrically along the long axis of the stadium, a magnetic field is applied along the short axis in the direction opposite to the remanent magnetization between the vortices, which is along the short axis.~ Two separate field regimes are observed. In the first, the vortices move as a function of the applied magnetic field toward one another on the center line. In the second, the vortices veer along the axis of the applied field to opposite straight sides of the stadium, annihilating at a critical field.~ The annihilation fields and successor states depend upon the relative polarization of the vortex cores.~ The results of the simulations are compared to recent experiments on the same system. [Preview Abstract] 

R1.00247: The electric and magnetic properties of titanium covered carbon nanotubes Sefa Dag, S. Ciraci We investigated the change of electrical and magnetic properties of Ti coated singlewall carbon nanotubes (SWNT). Our results have been obtained by the firstprinciples pseudopotential plane wave calculations within density functional theory. We have shown that a semiconducting SWNT can be covered uniformly by titanium atoms and form a complex but regular atomic structure [1]. The circular cross section changes to a squarelike form, and the system becomes metallic with high state density at the Fermi level and with high quantum ballistic conductance. Metallicity is induced not only by the metalmetal coupling, but also by the band gap closing of SWNT at the corners of the square. Even more interesting is that uniform titanium covered tubes have magnetic ground state with significant net magnetic moment and the semiconducting tube becomes ferromagnetic metal. However, the magnetic properties of Ti coated tubes depend strongly on the geometry, amount of Ti coverage and also on the elastic deformation of the tube [2]. While the magnetic moment can be pronounced significantly by the positive axial strain, it can decrease dramatically upon the adsorption of additional Ti atoms to those already covering the nanotube. Besides, electronic structure and spinpolarization near the Fermi level can also be modified by radial strain. [1] \textbf{S. Dag}, E. Durgun and S. Ciraci, Phys. Rev. B \textbf{69}, 121497(R) (2004). [2] \textbf{S. Dag} and S. Ciraci, Phys. Rev. B (In press, 2005) [Preview Abstract] 

R1.00248: Investigation of FarIR Phonon Modes of Nucleic Acids Xiaowei Li, Boris Gelmont, Maria Bykhovskaia, Tatiana Globus, Dwight Woolard We have performed the normal modes analysis of two nucleic acid molecules using AMBER in Cartesian coordinate space. The computational method that couples the normal modes of macromolecules with absorption spectra in the very far IR region (2300cm$^{1})$ is demonstrated. The calculated absorption spectrum of homopolymer poly[C]poly[G] RNA shows good correlation with experimental result as well as with the modeling spectrum based on the normal mode analysis using JUMNA {\&} LIGAND in internal coordinate space. The positions of resonance frequencies in the absorption spectrum of homopolymer poly[A]poly[T] DNA modeled by AMBER are very similar to those observed in the experiment. These encouraging results demonstrate the capability of the normal mode analysis to predicate the optical characteristics of macromolecules in terahertz gap. This work builds the foundation for future application of submillimeterwave spectroscopy technology in the identification and characterization of DNA and RNA molecules. [Preview Abstract] 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2018 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700