Orientational Order and Depinning of the Disordered Electron Solid

TL;DR

This paper investigates how disorder affects the structural order and depinning behavior of two-dimensional electron solids, revealing a transition from dislocation-only to dislocation-and-disclination configurations as disorder increases.

Contribution

It introduces a combined simulation and continuum elasticity approach to analyze the impact of impurity-induced disorder on electron solid ground states and depinning thresholds.

Findings

Disordered electron solids exhibit both dislocations and disclinations in strong disorder regimes.

The ground state becomes unstable against free disclinations at high dislocation densities.

The threshold electric field behavior changes with impurity setback distance.

Abstract

We study the ground state of two-dimensional classical electron solids under the influence of modulation-doped impurities by using a simulated annealing molecular dynamics method. By changing the setback distance as a parameter, we find that in the strong disorder limit the ground state configuration contains both isolated dislocations and disclinations, whereas in the weak disorder regime only dislocations are present. We show, via continuum elasticity theory, that the ground state of the lattice should be unstable against a proliferation of free disclinations above a critical dislocation density. Associated with this, the behavior of the threshold electric field as a function of the setback distance changes.