Phase diagram of the restricted solid-on-solid model coupled to the Ising model

TL;DR

This paper investigates the phase transitions of a coupled solid-on-solid and Ising model, revealing separate transition lines for surface roughening and Ising order, supported by precise Monte Carlo simulations.

Contribution

It provides the first detailed phase diagram showing that roughening and reconstruction transitions occur separately in the coupled model.

Findings

Two distinct phase transition lines identified: Ising and KT surface roughening.

The phase diagram shows the two transitions are separate across all studied parameters.

Supports the hypothesis that fully frustrated XY models have separate ordering transitions.

Abstract

We study the phase transitions of a restricted solid-on-solid model coupled to an Ising model, which can be derived from the coupled XY-Ising model. There are two kinds of phase transition lines. One is a Ising transition line and the other is surface roughening transition line. The latter is a KT transition line from the viewpoint of the XY model. Using a microcanonical Monte Carlo technique, we obtain a very accurate two dimensional phase diagram. The two transition lines are separate in all the parameter space we study. This result is strong evidence that the fully frustrated XY model orders by two separate transitions and that roughening and reconstruction transitions of crystal surfaces occur separately.