Effect of strain on stripe phases in the Quantum Hall regime

TL;DR

This study shows that applying external strain can control the orientation of stripe phases in the quantum Hall regime, revealing the influence of shear strain on charge density wave alignment in 2D electron and hole gases.

Contribution

It provides experimental and theoretical evidence that strain direction determines stripe phase orientation in quantum Hall systems, highlighting the role of shear strain in charge density wave behavior.

Findings

Stripe phase orientation can be controlled by external strain.

Shear strain influences the minimization of Hartree-Fock energy.

Internal electric fields induce shear strains affecting CDW orientation.

Abstract

Spontaneous breaking of rotational symmetry and preferential orientation of stripe phases in the quantum Hall regime has attracted considerable experimental and theoretical effort over the last decade. We demonstrate experimentally and theoretically that the direction of high and low resistance of the two-dimensional (2D) hole gas in the quantum Hall regime can be controlled by an external strain. Depending on the sign of the in-plane shear strain, the Hartree-Fock energy of holes or electrons is minimized when the charge density wave (CDW) is oriented along [110] or [1-10] directions. We suggest that shear strains due to internal electric fields in the growth direction are responsible for the observed orientation of CDW in pristine electron and hole samples.