Zero field Wigner crystal

TL;DR

This paper investigates the properties of a zero-field Wigner crystal in 2D electron systems, focusing on collective pinning effects, density dependence, and experimental signatures such as compressibility and conductivity.

Contribution

It introduces an elastic theory combined with Gaussian variational methods to analyze the zero-field Wigner crystal's physical properties and their experimental implications.

Findings

Density-dependent compressibility results

Predictions for dynamical conductivity and surface acoustic wave anomalies

Analysis of phonon emission and radiated power at finite temperatures

Abstract

A candidate for the insulating phase of the 2D electron gas, seen in high mobility 2D MOSFETS and heterojunctions, is a Wigner crystal pinned by the incipient disorder. With this in view, we study the effect of collective pinning on the physical properties of the crystal formed in zero external magnetic field. We use an elastic theory to describe to long wavelength modes of the crystal. The disorder is treated using the standard Gaussian variational method. We calculate various physical properties of the system with particular emphasis on their density dependence. We revisit the problem of compressibility in this system and present results for the compressibility obtained via effective capacitance measurements in experiments using bilayers. We present results for the dynamical conductivity, surface acoustic wave anomalies and the power radiated by the crystal through phonon emission at finite temperatures.