Driven Disordered Periodic Media with an Underlying Structural Phase Transition

TL;DR

This paper studies how a 2D crystal with a tunable structural phase transition responds to external driving forces, revealing complex dynamical states and phase coexistence relevant to superconductors and colloidal systems.

Contribution

It provides a detailed analysis of the dynamical states during depinning in a driven disordered 2D crystal with a structural phase transition, highlighting novel phase coexistence phenomena.

Findings

Identification of plastic flow, hexatic, and stabilized phases during depinning

Observation of phase coexistence regimes in driven disordered systems

Relevance to experimental systems like superconductors and colloids

Abstract

We investigate the driven states of a two-dimensional crystal whose ground state can be tuned through a square-triangular transition. The depinning of such a system from a quenched random background potential occurs via a complex sequence of dynamical states, which include plastic flow states, hexatics, dynamically stabilized triangle and square phases and intermediate regimes of phase coexistence. These results are relevant to transport experiments in the mixed phase of several superconductors which exhibit such structural transitions as well as to driven colloidal systems whose interactions can be tuned via surface modifications.