# Tuning of Fermi Contour Anisotropy in GaAs (001) 2D Holes via Strain

## TL;DR

This paper demonstrates that applying small in-plane strain to GaAs (001) 2D holes significantly alters their Fermi contour anisotropy, enabling in situ control for studying quantum phenomena.

## Contribution

It introduces a method to tune Fermi contour anisotropy in 2D holes via in-plane strain, revealing large anisotropy effects in a high-mobility GaAs system.

## Key findings

- Small strain induces large Fermi wavevector anisotropy (up to 3.3).
- Fermi anisotropy correlates with strain on the order of 10^{-4}.
- Method enables in situ control of anisotropy for quantum studies.

## Abstract

We demonstrate tuning of the Fermi contour anisotropy of two-dimensional (2D) holes in a symmetric GaAs (001) quantum well via the application of in-plane strain. The ballistic transport of high-mobility hole carriers allows us to measure the Fermi wavevector of 2D holes via commensurability oscillations as a function of strain. Our results show that a small amount of in-plane strain, on the order of $10^{-4}$, can induce significant Fermi wavevector anisotropy as large as 3.3, equivalent to a mass anisotropy of 11 in a parabolic band. Our method to tune the anisotropy \textit{in situ} provides a platform to study the role of anisotropy on phenomena such as the fractional quantum Hall effect and composite fermions in interacting 2D systems.