Surface reentrance in the semi-infinite spin-1 Ising models

TL;DR

This paper investigates the critical behavior and phase transitions, including surface reentrance phenomena, in semi-infinite spin-1 Ising models using the Cluster Variation Method, providing analytical expressions and phase diagrams.

Contribution

It presents analytical expressions for critical temperatures and classifies phase diagrams, revealing surface reentrant transitions in semi-infinite spin-1 Ising models.

Findings

Identification of surface first order transitions.

Existence of surface reentrant behavior under certain conditions.

Analytical expressions for critical temperatures.

Abstract

The critical behavior of the semi-infinite Blume-Capel and Blume-Emery-Griffiths models is investigated in the pair approximation of the Cluster Variation Method. Equations for bulk and surface order parameters and n.n. correlation functions are given, from which analytical expressions for the second order bulk and surface critical temperatures are derived. The phase diagrams of the Blume-Capel model are classified, and the existence of a surface first order transition is discussed. This transition is shown to be, under certain conditions, slightly reentrant, and the behavior of the surface order parameters and correlation functions is given for such a case. The extension of our results to the Blume-Emery-Griffiths model is briefly discussed.