Author ORCID Identifier

https://orcid.org/0000-0001-5821-1511

Date of Award

Fall 12-10-2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Ramesh G Mani

Second Advisor

Unil Perera

Third Advisor

Alexander Kozhanov

Fourth Advisor

Vadym Apalkov

Fifth Advisor

Piet Martens

Abstract

This dissertation summarizes the experimental study of novel magnetoresistance (MR) properties in the GaAs/AlGaAs 2D electron systems (2DES). The first part of the dissertation discusses the mutual influence between current-induced (IDC ) negative-giant magnetoresistance (GMR) and radiation-induced MR oscillations. The results show that MR oscillations do not modify the negative-GMR, and the MR oscillatory extrema disappear asymmetrically with increasing IDC. The second section discusses the influence of temperature on the weak localization-like narrow negative-MR effect that appears over the interval -0.025 ≤ B ≤ 0.025 Tesla. Results suggest that the narrow negative-MR effect could be due to coherent backscattering of electrons from remote ionized donors in the GaAs/AlGaAs system. The last section analyses the influence of microwave (MW) power on the narrow negative-MR effect. It turns out that the electrons heating due to the absorption of MW radiation suppresses the narrow negative-MR effect about the null magnetic field.

Available for download on Friday, November 29, 2019

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