Physics Commons^™

Theoretical Study Of Magnetoelectric Effects In Noncentrosymmetric And Cuprate Superconductors, Manoj Kumar Kashyap

Theses and Dissertations

A century after the discovery of superconductivity at the lab of Kamerlingh Onnes

in 1911, it is noticeable that the phenomenon is quite ubiquitous in nature. In addi-

tion to a long list of superconducting alloys and compounds, almost half the elements

in the periodic table superconduct. By the late seventies, superconductivity was

thought to be well understood. This turned out to be a myth, with the discovery of

unconventional superconductors that defied Bardeen-Cooper-Schrieffer (BCS) theory.

Cuprates have been the most prominent example among them ever since their discov-

ery in 1986 by Bednorz and M ̈uller. Another example of …

Surface Photovoltage Transients For P-Type Algan, Karen L. Phumisithikul

Theses and Dissertations

There is an understanding of surface photovoltage (SPV) behavior for GaN, yet little is known about the SPV behavior for AlGaN. In this work, a Kelvin probe was used to measure the SPV for p-type AlGaN. Very slow SPV transients were found in AlGaN, which could not be explained with a simple thermionic model. A possible explanation of this behavior is the segregation of impurities to the surface, which causes significant reduction of the depletion region width (down to 2 nm), with carrier tunneling and hopping becoming the dominant mechanisms responsible for the SPV transients. To verify this assumption, …

Silicon Nanostructures For High Capacity Anodes In Lithium Ion Batteries, Tyler M. Selden

Theses and Dissertations

In this study we looked at several different silicon nanostructures grown for the purpose of optimizing anodes for lithium ion batteries. We primarily focused on two distinct types of structures, nanospirals, and Rugate structures. The samples were designed to have the mechanical robustness to endure the massive expansion caused by lithiation of silicon. All of the samples were grown using an electron beam evaporator. Scanning electron microscope images show that we have achieved the desired structural growth. The spirals were shown to have an average diameter of 343 nm on polished copper, and 366 nm on unpolished copper. The Rugate …

Modeling The Defect Density Of States Of Disordered Sio2 Through Cathodoluminescence, Amberly Evans Jensen

Theses and Dissertations

Spacecraft charging is the accumulation of an electrical charge on orbiting spacecraft induced by the space plasma environment and has harmful effects on the electrical functionality of a spacecraft. This is studied extensively, particularly in the Materials Physics Group (MPG) at Utah State University (USU). During charging studies performed by the MPG, another potentially problematic effect of the space plasma environment on spacecraft was observed: light emanating from the sample undergoing electron beam bombardment. Space-based observatories are one type of spacecraft on which this luminescence may occur. If the luminescence from the material caused by the space plasma is within …