Noise and Thermal Depinning of Wigner Crystals

TL;DR

This study investigates how temperature affects the depinning threshold and conduction noise in driven Wigner crystals with quenched disorder, revealing temperature-dependent noise characteristics and phase distinctions.

Contribution

It provides new insights into temperature effects on depinning and noise in Wigner crystals, linking noise behavior to phase transitions and crystal dynamics.

Findings

Depinning threshold decreases with increasing temperature.

Noise power peaks at low temperatures and becomes more white at higher temperatures.

Washboard frequency signals disappear above melting temperature.

Abstract

We examine changes in the depinning threshold and conduction noise fluctuations for driven Wigner crystals in the presence of quenched disorder. At low temperatures there is a well defined depinning threshold and a strong peak in the noise power with $1/f$ noise characteristics. At higher temperatures, the depinning threshold shifts to lower drives and the noise, which is also reduced in power, becomes more white in character. At lower temperatures, a washboard frequency appears when the system depins elastically or forms a moving smectic state; however, this washboard signal is strongly reduced for higher temperatures and completely disappears above the melting temperature of a system without quenched disorder. Our results are in good agreement with recent transport and noise studies for systems where electron crystal depinning is believed to arise, and also show how noise can be used to distinguish between crystal, glass, and liquid phases.