Bulletin of the American Physical Society
Joint Spring 2010 Meeting of the Texas Sections of the APS, AAPT, and SPS
Volume 55, Number 3
Thursday–Saturday, March 18–20, 2010; Austin, Texas
Session C4: Condensed Matter Physics I |
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Chair: David Donnelly, Texas State University Room: Robert Lee Moore Hall 7.104 |
Friday, March 19, 2010 10:30AM - 10:42AM |
C4.00001: Resonantly driven coherent oscillations in a solid-state quantum emitter Edward Flagg, Andreas Muller, John Robertson, Sebastien Founta, Dennis Deppe, Min Xiao, Wenquan Ma, Gregory Salamo, Chih-Kang Shih The use of a single quantum emitter as a source to generate single photons has been a subject of much interest recently. Incoherent excitation, which is typically used in solid state systems in order to discriminate spectrally between the emission and the large amount of scattered input laser light, does not allow for direct coherent control of an emitter's quantum state, resulting in difficulty when attempting to use it as a single photon source. Coherent resonant excitation is used in pump-probe techniques, but does not enable the collection of the emitter's single photon emission. In this work, we demonstrate resonance fluorescence from a single semiconductor quantum dot in a microcavity absent of any significant background due to laser scattering. Under excitation from a strong continuous-wave laser field, the states of the quantum dot become `dressed', which we are able to observe from its Mollow-triplet emission spectrum. We are also able to measure its single photon emission characteristics, and observe oscillations in its second order correlation function. [Preview Abstract] |
Friday, March 19, 2010 10:42AM - 10:54AM |
C4.00002: A Study of Electromagnetic Wave Absorption Properties of Carbon Nanotubes-Based Composites at Microwave Frequencies Jim Roberts, Guang-Lin Zhao, Zhou Ye, Jin Tong Wang This paper focuses on the absorption properties of electromagnetic (EM) wave, both electric and magnetic, absorption properties of carbon nanotubes (CNTs)-based composites by using a resonant microwave cavity as a probe. The unusual properties of CNTs present new opportunities for creating new hybrid and multifunctional composite materials. However, these materials have largely been unexplored for their EM wave absorption properties. The objective of this research is a better understanding of the fabrications and characterizations of multi-walled carbon nanotubes (MWNTs)-based composites with a better understanding of the EM wave absorption properties of these materials to determine the feasibility of their application to electromagnetic shielding of satellites, pacemakers and radar target reduction. [Preview Abstract] |
Friday, March 19, 2010 10:54AM - 11:06AM |
C4.00003: Select Applications of Resonant Microwave Cavities Jim Roberts, Jai Dahiya Resonant circuits have been shown to be powerful as tools to measure both magnetic and electrical properties of matter. In this discussion we present the results of some of the applications of the resonant cavity as a probe to monitor both first order and second order phase change. One experiment that produced interesting data is the change in water as it changes from ice to water. Data that showed large variation near the transition temperature will be explored to help gain insight into hydrogen bonding and how this activity may be used to understand the formation of snowflakes in such various patterns. Perturbation equations for resonant cavities will be explored to help better understand the degree of accuracy measurements can be made. Special fields within the cavity will be discussed with some limitations proposed on how relative measurements can be useful, although absolute measurements may not be highly accurate. High Q resonant cavities are powerful tools. [Preview Abstract] |
Friday, March 19, 2010 11:06AM - 11:18AM |
C4.00004: Quantum Engineering of Ultra-thin Films for Plasmonic Studies Charlotte Sanders, Jisun Kim, B.-H. Li, James McIlhargey, Xianggang Qiu, Gennady Shvets, C.K. Shih The plasmonic properties of polycrystalline films are presumed to be strongly affected by grain boundary scattering and consequent damping of plasmonic resonances. However, to date there have been few systematic studies comparing plasmonic measurements in polycrystalline and single crystal films. Extraordinary optical transmission (EOT) is the phenomenon of strongly enhanced optical transmission through subwavelength apertures in metallic films, and results from coupling between incident light and plasmons on the film surface. In this talk we will present data comparing the plasmonic properties of single- and polycrystalline Ag thin films probed using EOT in the far- and mid-infrared regimes, and will discuss the epitaxial growth methods used to obtain highly perfect single-crystal films. Our findings show strong plasmonic enhancement in the single-crystal samples at key resonances, as well as suppression at certain wave numbers. The data will also be compared with results of simulation. [Preview Abstract] |
Friday, March 19, 2010 11:18AM - 11:30AM |
C4.00005: Investigation of Strain in Si Materials Using Micro-Raman Spectroscopy Logan Hancock, Toni Sauncy, Tim Dallas In this study, micro-Raman spectroscopy has been used to probe for the presence of strain in two silicon structures of particular interest. The first involves examination of strain in a series of porous Silicon (pSi) thin films, prepared by photo etching, to yield information regarding the integrity and quality of the thin-films. The second study is a collaboration with the Texas Tech University Department of Electrical Engineering to examine the strain within a silicon-based microelectromechanical systems (MEMS) chevron/distance-multiplier device during actuation and to the point of device failure. [Preview Abstract] |
Friday, March 19, 2010 11:30AM - 11:42AM |
C4.00006: Integration of functional complex oxides on silicon using molecular beam epitaxy Agham Posadas, Miri Choi, Rytis Dargis, Alex Demkov Complex oxides exhibit a wide range of electronic properties, including high temperature superconductivity, colossal magnetoresistance, metal-insulator transitions, ferromagnetism, and ferroelectricity. Interesting devices and sensors could be envisioned by fabricating these oxides in epitaxial, thin film form on silicon, the most widely used materials platform for electronic devices. However, integrating the functionality of complex oxides onto silicon turns out to be a very difficult problem. One needs to be able to deposit an oxide in crystalline form on top of silicon without forming SiO$_{2}$, which grows amorphous and destroys the underlying crystalline order of the substrate surface causing subsequently deposited films to be highly defective. In this talk, we will first describe the new oxide molecular beam epitaxy capabilities at the Materials Physics Laboratory in UT Austin, and then briefly discuss a process by which one can smoothly transition from the oxygen-sensitive, covalently bonded silicon substrate to a fully oxidized, ionically bonded perovskite oxide layer (SrTiO$_{3})$ using a carefully sequenced deposition of various atomic layers. This capability opens up the possibility of depositing these functional oxide materials in epitaxial form onto silicon. [Preview Abstract] |
Friday, March 19, 2010 11:42AM - 11:54AM |
C4.00007: Investigation of Gadolinium Gallium Oxide using spectroscopic ellipsometry Kunal Bhatnagar, Toni Sauncy, Ravi Droopad Spectroscopic Ellipsometry (SE) is a non-destructive characterization technique used for determining film thickness, interfacial roughness and optical properties of single and multilayered materials. SE measures the change in the polarization state of the incident light upon reflection from these layers providing insight into the properties and composition of topmost and underlying materials. The Horiba Jobin Yvon - UVISEL located in the Angelo State Materials Characterization Lab is based on the principle of phase modulated spectroscopic ellipsometry. This tool has been used to successfully characterize a variety of semiconductor samples. We will detail results from semiconductor heterostructures containing Gadolinium Gallium Oxide (GdGaO$_{3})$, a novel material with promise for application as a high-k dielectric in the design of compound semiconductor MOSFETs. Models for this unusual material have been developed and used to characterize various structures with success. We have obtained reasonable values for electrical and optical parameters for the GGO not found in current literature. [Preview Abstract] |
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