Study of Domains in the Ground State of the Two Dimensional Coulomb Glass

TL;DR

This study uses Monte Carlo simulations to analyze the ground state domains of a two-dimensional Coulomb glass, revealing a first-order phase transition and challenging existing theoretical assumptions about domain structure.

Contribution

It provides new insights into the domain energy scaling, phase transition nature, and the limitations of Imry-Ma arguments in Coulomb glasses.

Findings

Domain energy scales as L^{d-1}

First-order transition indicated by discontinuity in magnetization

Inconsistency with Imry-Ma assumptions about domain fluctuations

Abstract

We have annealed two dimensional lattice model of Coulomb glass using Monte Carlo simulations to obtain the ground state. We have shown that the energy required to create a domain of linear size L in d dimensions is proportional to $L^{d-1}$. Using Imry-Ma arguments given for RFIM, one gets $d_{c}\geq 2$ for Coulomb glass. The investigations in the transition region shows that the domain wall of the metastable state in the charge-ordered phase shifts as disorder is increased to give disordered ground state at higher disorder strength indicating phase coexistence. This coupled with discontinuity in magnetization is an indication of first-order type transition from charge-ordered phase to disordered phase. The structure and nature of Random field fluctuations of the domain in Coulomb glass are inconsistent with the assumptions of Imry and Ma as was also reported for RFIM.