Zero-field spin splitting and spin-dependent broadening in high-mobility InSb/In1−xAlxSb asymmetric quantum well heterostructures

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Title: Zero-field spin splitting and spin-dependent broadening in high-mobility InSb/In1−xAlxSb asymmetric quantum well heterostructures
Author(s): Gilbertson, AM
Branford, WR
Fearn, M
Buckle, L
Buckle, PD
Ashley, T
Cohen, LF
Item Type: Journal Article
Abstract: We present high field magneto-transport data from a range of 30nm wide InSb/InAlSb quantum wells. The low temperature carrier mobility of the samples studied ranged from 18.4 to 39.5 m2V-1s-1 with carrier densities between 1.5x1015 and 3.28x1015 m-2. Room temperature mobilities are reported in excess of 6 m2V-1s-1. It is found that the Landau level broadening decreases with carrier density and beating patterns are observed in the magnetoresistance with non-zero node amplitudes in samples with the narrowest broadening despite the presence of a large g-factor. The beating is attributed to Rashba splitting phenomenon and Rashba coupling parameters are extracted from the difference in spin populations for a range of samples and gate biases. The influence of Landau level broadening and spin-dependent scattering rates on the observation of beating in the Shubnikov-de Haas oscillations is investigated by simulations of the magnetoconductance. Data with non-zero beat node amplitudes are accompanied by asymmetric peaks in the Fourier transform, which are successfully reproduced by introducing a spin-dependent broadening in the simulations. It is found that the low-energy (majority) spin up state suffers more scattering than the high-energy (minority) spin down state and that the absence of beating patterns in the majority of (lower density) samples can be attributed to the same effect when the magnitude of the level broadening is large.
Publication Date: 26-Jun-2009
Date of Acceptance: 26-Jun-2009
URI: http://hdl.handle.net/10044/1/32143
DOI: http://dx.doi.org/10.1103/PhysRevB.79.235333
ISSN: 1550-235X
Publisher: American Physical Society
Journal / Book Title: Physical Review B
Volume: 79
Copyright Statement: This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Funder's Grant Number: EP/C511972/1
Keywords: cond-mat.mes-hall
cond-mat.mes-hall
Fluids & Plasmas
02 Physical Sciences
03 Chemical Sciences
Publication Status: Published
Article Number: 235333
Appears in Collections:Physics
Experimental Solid State
Faculty of Natural Sciences



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