On the impact of strain on the electronic properties of InAs/GaSb quantum well systems

TL;DR

This study investigates how externally applied strain affects the electronic transport and Landau level structure in InAs/GaSb quantum wells, revealing strain-dependent modifications to their semimetallic behavior.

Contribution

It provides a combined experimental and theoretical analysis of strain effects on InAs/GaSb quantum wells, highlighting the strain's role in their electronic properties and semimetallic nature.

Findings

Strain significantly alters resistivity at the charge neutrality point.

External strain influences Landau level structures.

Intrinsic and external strains together explain semimetallic behavior.

Abstract

Electron-hole hybridization in InAs/GaSb double quantum well structures leads to the formation of a mini band gap. We experimentally and theoretically studied the impact of strain on the transport properties of this material system. Thinned samples were mounted to piezo electric elements to exert strain along the [011] and [001] crystal directions. When the Fermi energy is tuned through the mini gap, a dramatic impact on the resistivity at the charge neutrality point is found which depends on the amount of applied external strain. In the electron and hole regimes, strain influences the Landau level structure. By analyzing the intrinsic strain from the epitaxial growth, the external strain from the piezo elements and combining our experimental results with numerical simulations of strained and unstrained quantum wells, we compellingly illustrate why the InAs/GaSb material system is regularly found to be semimetallic.