Phase transitions in the Mitsui model

TL;DR

This paper investigates phase transitions in the Mitsui model with transverse field using mean field approximation, establishing phase diagrams and analytical conditions for tricritical points, enhancing understanding of ferroelectric phase behavior.

Contribution

It introduces a detailed analysis of phase transitions in the Mitsui model with transverse field, deriving analytical expressions and conditions for tricritical points.

Findings

Analytical expression for tricritical temperature at zero transverse field

Conditions for the existence of tricritical points with non-zero transverse field

Construction of phase diagrams and ferroelectric phase boundaries

Abstract

In this paper, phase transitions in the Mitsui model without longitudinal field but with a transverse one are investigated in the mean field approximation. The one-to-one correspondence has been established between this model and the two-sublattice Ising-type model with longitudinal and transverse fields. Phase diagrams and diagrams of existence of the ferroelectric phase are constructed. In the case $\Omega =0$ ($\Omega$ is the transverse field), a simple analytical expression for the tricritical temperature and the condition of existence of the tricritical point are obtained. For $\Omega \ne 0$, systems of equations for the tricritical point and for the condition of its existence are written.