Heisenberg model in a random field: phase diagram and tricritical behavior

TL;DR

This paper investigates the phase diagram and tricritical behavior of the spin-1/2 Heisenberg model in a bimodal random field using effective field theory, revealing complex phase transitions on square and cubic lattices.

Contribution

It introduces a detailed analysis of the tricritical behavior of the Heisenberg model in a random field using differential operator and effective field theory methods.

Findings

Identification of phase boundaries in T-h plane

Observation of tricritical points in the phase diagram

Differences between square and cubic lattice behaviors

Abstract

By using the differential operator technique and the effective field theory scheme we study the tricritical behavior of Heisenberg classical model of spin-1/2 in a random field. The phase diagram in the T-h plane on a square and simple cubic lattice for a cluster with two spins is obtained when the random field is bimodal distributed.