Date of Award

5-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Physics

Committee Chair/Advisor

Dr. Catalina Marinescu

Committee Member

Dr. Sumanta Tewari

Committee Member

Dr. Jian He

Committee Member

Dr. Emil Alexov

Abstract

In this thesis we analyze two different situations where the interplay between the spin-orbit coupling (SOI) of the Rashba and Dresselhaus type, linear in the elec-tron momentum, and the Coulomb interaction generates a specific macroscopic phe-nomenology that can be experimentally observed. In the first problem, we investigate the Friedel oscillations that can be sustained in in the presence of the Coulomb repul-sion in a two-dimensional lateral superlattice with SOI and analyze the dependence on several system parameters. Then, we are concerned with the properties of a single quantum well in the special regime where the coupling strengths of the Rashba and Dresselhaus interactions are equal. Starting from general total-energy considerations, we demonstrate that the SU(2) spin-rotation symmetry and the resulting persistent helical state (PHS) predicted to occur are not in fact realized; the actual spin order being that of an itinerant antiferromagnet (IAF). We obtain numerical results that describe the temperature evolution of the order parameter in the IAF state and deter-mine the critical temperature of the transition to the paramagnetic order. Transport in this state is modeled by using the solutions of a Boltzmann equation obtained within the relaxation time approximation. Numerical estimates performed for realistic GaAs and InAs samples indicate that at low temperatures, the amplitude of the spin-Seebeck coefficient can be increased by scattering on magnetic impurities.

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