Diversity enabling equilibration: disorder and the ground state in artificial spin ice

TL;DR

This study explores how disorder influences the ability of artificial spin ice systems to reach their ground state, revealing that both quenched and driving field disorder can lower the system's energy and facilitate equilibration.

Contribution

The paper introduces a novel approach showing that disorder in artificial spin ice can promote ground state attainment by creating new dynamical pathways.

Findings

Quenched disorder can lead to lower energy final states.

Disorder in driving fields consistently reduces the system's energy.

Disorder enhances the dynamical pathways available for equilibration.

Abstract

We report a novel approach to the question of whether and how the ground state can be achieved in square artificial spin ices where frustration is incomplete. We identify two types of disorder: quenched disorder in the island response to fields and disorder in the sequence of driving fields. Numerical simulations show that quenched disorder can lead to final states with lower energy, and disorder in the driving fields always lowers the final energy attained by the system. We use a network picture to understand these two effects: disorder in island responses creates new dynamical pathways, and disorder in driving fields allows more pathways to be followed.