Thermodynamic description of the Ising antiferromagnet on triangular lattice with selective dilution by modified Pair Approximation method

TL;DR

This paper extends the Pair Approximation method to better describe geometrically frustrated systems, specifically the Ising antiferromagnet on a triangular lattice with selective dilution, providing a thermodynamic phase diagram and improved analysis.

Contribution

The paper introduces a modified Pair Approximation method for thermodynamic analysis of frustrated magnetic systems, applied to the Kaya-Berker model with detailed phase diagram construction.

Findings

Thermodynamic quantities are accurately described with the modified method.

The phase diagram reveals the effects of selective dilution on magnetic ordering.

Comparison shows the improved accuracy over traditional methods.

Abstract

The Pair Approximation method is modified in order to describe the systems with geometrical frustration. The Ising antiferromagnet on triangular lattice with selective dilution (Kaya-Berker model) is considered and a self-consistent thermodynamic description of this model is obtained. For this purpose, the Gibbs free-energy as a function of temperature, concentration of magnetic atoms on the selected sublattice, and external magnetic field is derived. In particular, the phase diagram is constructed and a comparison of different methods is presented. The thermodynamic quantities are discussed in the context of their physical validity and the improvement in the description introduced by modified method is emphasized.