Universality class of a displacive structural phase transition in two dimensions

TL;DR

This paper investigates a two-dimensional displacive structural phase transition, demonstrating it belongs to the six-state clock model universality class, and identifies its three distinct thermodynamic phases through Monte Carlo simulations.

Contribution

It establishes the universality class of a specific 2D structural transition and characterizes its phase diagram using finite-size scaling.

Findings

The transition belongs to the six-state clock model universality class.

The model exhibits three thermodynamic phases.

There are two phase transitions separating these phases.

Abstract

The displacive structural phase transition in a two-dimensional model solid due to Benassi and co-workers [PRL 106, 256102 (2011)] is analyzed using Monte Carlo simulations and finite-size scaling. The model is shown to be a member of the two-dimensional six-state clock model universality class. Consequently, the model features two phase transitions, implying the existence of three thermodynamically distinct phases, namely, a low-temperature phase with long-ranged order, an intermediate critical phase with power-law decay of correlations, and a high-temperature phase with short-ranged order.