Modification of smeared phase transitions by spatial disorder correlations

TL;DR

This paper investigates how spatial disorder correlations influence smeared phase transitions, revealing that even short-range correlations can significantly alter the behavior of the order parameter in disordered systems.

Contribution

It introduces a theoretical framework and simulation results showing the impact of short-range spatial disorder correlations on smeared phase transitions.

Findings

Positive correlations enhance the order parameter

Repulsive correlations suppress the order parameter

Short-range correlations qualitatively modify phase transition behavior

Abstract

Phase transitions in disordered systems can be smeared if rare spatial regions develop true static order while the bulk system is in the disordered phase. Here, we study the effects of spatial disorder correlations on such smeared phase transitions. The behaviors of observables are determined within optimal fluctuation theory. We show that even short-range correlations can qualitatively modify smeared phase transitions. For positive correlations (like impurity atoms attract each other), the order parameter is enhanced, while it is suppressed for repulsive correlations (like atoms repel each other). We use computer simulations to generate various types of disorder correlations, and to verify our theoretical predictions.