Strain-induced Fermi contour anisotropy of GaAs 2D holes

TL;DR

This study measures how in-plane strain affects the shape and anisotropy of Fermi contours in GaAs 2D holes, revealing strain-tunable distortions consistent with theoretical predictions.

Contribution

It provides the first direct experimental observation of strain-induced Fermi contour anisotropy in GaAs 2D holes, confirming theoretical models.

Findings

Majority spin-subband Fermi contour is severely distorted.

Anisotropy of Fermi contours can be tuned with strain.

Experimental results agree quantitatively with band calculations.

Abstract

We report measurements of magneto-resistance commensurability peaks, induced by a square array of anti-dots, in GaAs (311)A two-dimensional holes as a function of applied in-plane strain. The data directly probe the shapes of the Fermi contours of the two spin subbands that are split thanks to the spin-orbit interaction and strain. The experimental results are in quantitative agreement with the predictions of accurate energy band calculations, and reveal that the majority spin-subband has a severely distorted Fermi contour whose anisotropy can be tuned with strain.