Phase Ordering Kinetics of the Asymmetric Coulomb Glass Model

TL;DR

This study investigates phase ordering kinetics in the asymmetric Coulomb glass model, revealing that domain growth follows a slightly slower law than classical models, possibly indicating logarithmic growth at long times.

Contribution

It is the first to analyze phase ordering in the asymmetric Coulomb glass model without quenched disorder, showing universality with ferromagnetic ordering and identifying deviations from standard growth laws.

Findings

Domain growth is in the same universality class as ferromagnetic ordering.

Growth law is slightly slower than t^{1/2}, suggesting possible logarithmic growth.

No explicit quenched disorder, but frustration influences dynamics.

Abstract

We present results for phase ordering kinetics in the {\it Coulomb glass} (CG) model, which describes electrons on a lattice with unscreened Coulombic repulsion. The filling factor is denoted by $K \in [0,1]$. For a square lattice with $K=0.5$ (symmetric CG), the ground state is a checkerboard with alternating electrons and holes. In this paper, we focus on the asymmetric CG where $K \lesssim 0.5$, i.e., the ground state is checkerboard-like with excess holes distributed uniformly. There is no explicit quenched disorder in our system, though the Coulombic interaction gives rise to frustration. We find that the evolution morphology is in the same dynamical universality class as the ordering ferromagnet. Further, the domain growth law is slightly slower than the {\it Lifshitz-Cahn-Allen} law, $L(t) \sim t^{1/2}$, i.e., the growth exponent is underestimated. We speculate that this could be a signature of logarithmic growth in the asymptotic regime.