Accession Number : ADA564865


Title :   Magnetotransport in Two Dimensional Electron Systems Under Microwave Excitation and in Highly Oriented Pyrolytic Graphite


Corporate Author : GEORGIA STATE UNIV ATLANTA


Personal Author(s) : Ramanayaka, Aruna N


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a564865.pdf


Report Date : Jan 2012


Pagination or Media Count : 104


Abstract : This thesis consists of two parts. The first part considers the e 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 omegaC and the MW angular frequency satisfy 2omega= omegac = 3:5omega. The results indicate negligible electron heating under modest MW photoexcitation, in agree ment 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.


Descriptors :   *MAGNETORESISTANCE , *MICROWAVES , *PYROLYTIC GRAPHITE , ANGULAR MOTION , CYCLOTRONS , GALLIUM ARSENIDES , GRAPHITE , HALL EFFECT , HEATING , MAGNETIC PROPERTIES , MATHEMATICAL PREDICTION , OSCILLATION , POLARIZATION , RADIATION , TEMPERATURE , TRANSPORT PROPERTIES


Subject Categories : Electricity and Magnetism


Distribution Statement : APPROVED FOR PUBLIC RELEASE