Non-activated transport of strongly interacting two-dimensional holes in GaAs

TL;DR

This study investigates transport properties of ultra-dilute two-dimensional holes in GaAs, revealing non-activated, power-law temperature dependence in highly pure samples, contrasting with activated behavior in disordered systems.

Contribution

It provides new insights into non-activated transport mechanisms in strongly interacting 2D hole systems at extremely low densities.

Findings

Non-activated conductivity grows with temperature following a power law.

Transport behavior differs significantly from disordered samples showing activated transport.

Record low densities achieved in high-quality GaAs 2D hole systems.

Abstract

We report on the transport measurements of two-dimensional holes in GaAs field effect transistors with record low densities down to 7*10^8 cm^{-2}. Remarkably, such a dilute system (with Fermi wavelength approaching 1 micrometer) exhibits a non-activated conductivity that grows with temperature following a power law. We contrast it with the activated transport obtained from measuring more disordered samples, and discuss possible transport mechanisms in this strongly-interacting regime.