Date of Award
8-7-2012
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Physics and Astronomy
First Advisor
Dr. Ramesh Mani
Second Advisor
Dr. Unil Perera
Third Advisor
Dr. Vadym Apalkov
Fourth Advisor
Dr. Murad Sarsour
Fifth Advisor
Dr. Douglas Gies
Abstract
This thesis consists of two parts. The first part considers the effect of microwave radiation on magnetotransport in high quality GaAs/AlGaAs heterostructure two dimensional electron systems. The effect of microwave (MW) radiation on electron temperature was studied by investigating the amplitude of the Shubnikov de Haas (SdH) oscillations in a regime where the cyclotron frequency $\omega_{c}$ and the MW angular frequency $\omega$ satisfy $2\omega \leq \omega_{c} \leq 3.5\omega$. The results indicate negligible electron heating under modest MW photoexcitation, in agreement with theoretical predictions. Next, the effect of the polarization direction of the linearly polarized MWs on the MW induced magnetoresistance oscillation amplitude was investigated. The results demonstrate the first indications of polarization dependence of MW induced magnetoresistance oscillations. In the second part, experiments on the magnetotransport of three dimensional highly oriented pyrolytic graphite (HOPG) reveal a non-zero Berry phase for HOPG. Furthermore, a novel phase relation between oscillatory magneto- and Hall- resistances was discovered from the studies of the HOPG specimen.
DOI
https://doi.org/10.57709/3097071
Recommended Citation
Ramanayaka, Aruna N., "Magnetotransport in Two Dimensional Electron Systems Under Microwave Excitation and in Highly Oriented Pyrolytic Graphite." Dissertation, Georgia State University, 2012.
doi: https://doi.org/10.57709/3097071