Phase diagram for Coulomb-frustrated phase separation in systems with negative short-range compressibility

TL;DR

This paper maps the phase diagram of Coulomb frustrated phase separation in systems with negative short-range compressibility, revealing complex transition behaviors and lattice structures near critical points.

Contribution

It provides a detailed phase diagram using numerical and asymptotic methods, highlighting the effects of anisotropy and identifying various lattice configurations.

Findings

First-order transition from homogeneous to inhomogeneous phases in 3D systems.

Formation of BCC lattice near the critical point.

Presence of a tricritical point with anisotropy inclusion.

Abstract

Using numerical techniques and asymptotic expansions we obtain the phase diagram of a paradigmatic model of Coulomb frustrated phase separation in systems with negative short-range compressibility. The transition from the homogeneous phase to the inhomogeneous phase is generically first order in isotropic three-dimensional systems except for a critical point. Close to the critical point, inhomogeneities are predicted to form a BCC lattice with subsequent transitions to a triangular lattice of rods and a layered structure. Inclusion of a strong anisotropy allows for second- and first-order transition lines joined by a tricritical point.