Bulletin of the American Physical Society
2005 Ohio Sections of the APS and AAPT Joint Fall Meeting
Friday–Saturday, October 14–15, 2005; Cleveland, OH
Session D2: Solid State - Theory |
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Chair: Michael Crescimanno Room: Cleveland State University 1 |
Saturday, October 15, 2005 9:30AM - 9:42AM |
D2.00001: Theory of the band offset at the Si(100)-SiO$_2$ interface Blair Tuttle The valence band offset at device quality interfaces between Si(001) and SiO$_2$ are investigated using local density functional electronic structure calculations. Several model interfaces have been examined. One includes a relaxed amorphous oxide and several hundred atoms. The experimental band offset results are re-examined in the context of these calculations. \newline \newline [1] B. Tuttle, Phys. Rev. B {\bf 70}, 125322 (2004). [Preview Abstract] |
Saturday, October 15, 2005 9:42AM - 9:54AM |
D2.00002: Band Structure of Helical Carbon Nanotubes Gian Guzman-Verri, Lok Lew Van Yoon In this talk we present band structure calculations of single-wall helical carbon nanotubes obtained by effective-mass theory. [Preview Abstract] |
Saturday, October 15, 2005 9:54AM - 10:06AM |
D2.00003: Hidden symmetry and spin-splitting effects of electron dispersion in narrow-band semiconductor films. Leonid Isaev, Yong Joe, Arkady Satanin It is well known that in the effective mass approximation electron and hole states in bulk lead salt compounds [such as $Pb_{1-x} Sn_x (Se,S)$] can be well described by the two-band model with the Dirac-type effective Hamiltonian. We use this model to investigate the electron spectrum of films with the forbidden band width modulated in (111) (growth) direction. It is found that in a bulk crystal the wave equation for electrons may be reformulated in a supersymmetrical form, which gives a key to understanding the two-fold degeneracy of the spectrum. The film boundaries, in general, destroy the supersymmetry, i.e. size-quantized subbands turn out to be spin-split. However, there exists a class of boundary conditions that do not lift the spin degeneracy. Our central statement is that even when the system does not posses inversion symmetry, which is destroyed by the bulk inhomogeneity, the spin-splitting of the spectrum is a purely surface effect. This is illustrated on an exactly solvable example, when the energy gap varies linearly over the film width. Similar arguments can be applied to more accurate Dimmock's model. Our results then indicate the inconsistency of the widely used boundary conditions when the envelope wavefunction vanishes at the surface of the system and show a new direction to control electron spin states. [Preview Abstract] |
Saturday, October 15, 2005 10:06AM - 10:18AM |
D2.00004: Fano Resonance in Photonic Crystals and Quantum Mechanics Solomon Duki, Francesc Ferrer, H. Mathur We study the resonant transmission through a photonic crystal channel drop device. The frequency dependence of the resonant transmission is shown to have an asymmetric Fano line shape. In contrast to previous work [1] we find the symmetric Lorentzian line shape results only under special conditions of high device symmetry. We also study quantum systems in which the resonant scattering cross section has an asymmetric Fano line shape as a function of energy. Surprisingly the associated long-lived quasi-bound state under goes simple exponential decay, just as it would in the symmetric Lorentzian case. \newline \newline [1] Shanhui Fan, Pierre R. Villeneuve, and J. D. Joannopoulos PRB 59, 15882 (1999) [Preview Abstract] |
Saturday, October 15, 2005 10:18AM - 10:30AM |
D2.00005: Cubic is not Isotropic! John Platig, Lok Lew Yan Voon All standard literature, including textbooks such as Landau and Lifshiftz, state that cubic crystals are isotropic. In this talk we explain the difference between the above statement and experimental results indicating otherwise. [Preview Abstract] |
Saturday, October 15, 2005 10:30AM - 10:42AM |
D2.00006: A Theoretical perspective on N-resonance spectroscopy Michael Crescimanno, Michael Hohensee, David Phillips, Irina Novikova, Ronald Walsworth Recent experimental studies using the N-resonance [1,2] as a basis for secondary time standards are promising since they can be scaled small and enjoy competitive performance using D2 optical transition in Rubidium for which sources are cheaper and more readily available. There are essentaily four distinct hyperfine N-resonances in the D-system of alkalis (two of which have been studied experimentally), and it is apriori unclear which of the four are best suited for clock applications. We highlight the development and use of a theoretical quantum optics model using a truncated floquet solver to compare the figure of merits of the various N-resonances in the Rubidium D-system for potential clock applications. A simplified version of the model provides some insight into the physics behind the differences found. \newline [1] ``Observation of a three-photon electromagnetically induced transparency in hot atomic vapor,'' A.S. Zibrov (Harvard/Lebedev), C.Y. Ye, Y.V. Rostovtsev, A.B. Matsko, and M.O. Scully (TAMU) Phys. Rev. A, 65, (2002) pg. 043817. [2] ``A novel absorption resonance for all-optical atomic clocks,'' S. Zibrov, I. Novikova, D.F. Phillips (Harvard-Smithsonian), A.V. Taichenachev, V.I. Yudin (LLF/Novosibirsk), R.L. Walsworth (Harvard-Smithsonian), and A.S. Zibrov (Harvard/Lebedev), physics/0501090, Jan 2005. [Preview Abstract] |
Saturday, October 15, 2005 10:42AM - 10:54AM |
D2.00007: Interlevel optical properties of quantum dots: some unexpected problems and their solutions Victor Bondarenko Optical properties of quantum dot (QD) systems due to interlevel transitions of electrons in the dots are investigated. Electron-electron interaction in the QD systems is in the focus of the consideration. We show how the problem of electron self-interaction appears in QDs and how to solve it. We present convenient tools for handling the electron-electron interactions in QDs. Principal importance of careful consideration of QD shape and polarization direction of incident radiation for correct interpretation and prediction of the optical properties of QDs is shown. Some fundamental aspects of the electromagnetic response of QDs are revealed which is important for designing, manufacturing, and exploiting nanooptoelectronic devices based on QDs. [Preview Abstract] |
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