Characterization and Efficient Monte Carlo Sampling of Disordered Microphases

TL;DR

This paper thoroughly characterizes disordered microphases in a SALR model, devises structural relaxation functions, and evaluates the efficiency of advanced Monte Carlo sampling schemes for different regimes.

Contribution

It provides a detailed characterization of disordered microphases and benchmarks the efficiency of various Monte Carlo sampling methods for these complex systems.

Findings

VMMC+AVBMC is most efficient for cluster fluids

ECMC becomes more efficient at higher densities

Complete description of equilibrium disordered phase achieved

Abstract

The disordered microphases that develop in the high-temperature phase of systems with competing short-range attractive and long-range repulsive (SALR) interactions result in a rich array of distinct morphologies, such as cluster, void cluster and percolated (gel-like) fluids. These different structural regimes exhibit complex relaxation dynamics with significant relaxation heterogeneity and slowdown. The overall relationship between structure and configurational sampling schemes, however, remains largely uncharted. In this article, the disordered microphases of a schematic SALR model are thoroughly characterized, and structural relaxation functions adapted to each regime are devised. The sampling efficiency of various advanced Monte Carlo (MC) sampling schemes--Virtual-Move (VMMC), Aggregation-Volume-Bias (AVBMC) and Event-Chain (ECMC)--is then assessed. A combination of VMMC and AVBMC is found to be computationally most efficient for cluster fluids and ECMC to become relatively more efficient as density increases. These results offer a complete description of the equilibrium disordered phase of a simple microphase former as well as dynamical benchmarks for other sampling schemes.