Temperature-dependent Drude transport in a two-dimensional electron gas

TL;DR

This paper investigates how different impurities affect the temperature-dependent conductivity of dilute two-dimensional electron gases, revealing signatures that help characterize disorder types and cautioning against misinterpreting metallic or insulating behaviors.

Contribution

It provides a detailed analysis of impurity-specific signatures in temperature-dependent Drude conductivity for 2D electron gases, highlighting the role of energy-dependent scattering.

Findings

Neutral impurities cause a slow decrease in conductivity with temperature.

Charged impurities lead to conductivity increasing as the square root of temperature.

Impurity signatures can be used to characterize sample disorder composition.

Abstract

We consider transport of dilute two-dimensional electrons, with temperature between Fermi and Debye temperatures. In this regime, electrons form a nondegenerate plasma with mobility limited by potential disorder. Different kinds of impurities contribute unique signatures to the resulting temperature-dependent Drude conductivity, via energy-dependent scattering. This opens up a way to characterize sample disorder composition. In particular, neutral impurities cause a slow decrease in conductivity with temperature, whereas charged impurities result in conductivity growing as a square root of temperature. This observation serves as a precaution for literally interpreting metallic or insulating conductivity dependence, as both can be found in a classical metallic system.