Pseudospin transfer torques and the effect of disorder in semiconductor electron bilayers

Kim, Youngseok

Permalink

https://hdl.handle.net/2142/31211 Copy

Description

Title

Pseudospin transfer torques and the effect of disorder in semiconductor electron bilayers

Author(s)

Kim, Youngseok

Issue Date

2012-05-22T00:35:53Z

Director of Research (if dissertation) or Advisor (if thesis)

Gilbert, Matthew J.

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Pseudospin ferromagnetism
• semiconductor bilayer

Abstract

We use self-consistent quantum transport theory to investigate the influence of electron-electron interactions on interlayer transport in semiconductor electron bilayers in the absence of an external magnetic fi eld. We conclude that, even though spontaneous pseudospin order does not occur at zero field, interaction-enhanced quasiparticle tunneling amplitudes and pseudospin transfer torques do alter tunneling I-V characteristics, and can lead to time-dependent response to a dc bias voltage. In addition, we study the eff ects of disorder on the interlayer transport properties of disordered semiconductor bilayers. We find that the addition of material disorder to the system affects interlayer interactions leading to signifi cant deviations in the interlayer transfer characteristics. In particular, we find that disorder decreases and broadens the tunneling peak, eff ectively reducing the interacting system to a non-interacting system. Our results suggest that the experimental observation of interaction-enhanced interlayer transport in semiconductor bilayers requires materials with mean-free paths larger than the spatial extent of the system.

Graduation Semester

2012-05

Permalink

http://hdl.handle.net/2142/31211

Copyright and License Information

Copyright 2012 Youngseok Kim

Owning Collections