Phase diagram of the asymmetric tetrahedral Ising-Heisenberg chain

TL;DR

This paper investigates the ground state phase diagram and thermodynamic properties of an asymmetric tetrahedral Ising-Heisenberg chain, revealing complex phases and multicritical points through exact mapping and decorated transformations.

Contribution

It introduces a novel asymmetric tetrahedral chain model with mixed Ising-Heisenberg interactions and provides exact analysis of its phase diagram and thermodynamics.

Findings

Rich phase diagram with multicritical points

Exact mapping to an effective Ising chain

Feasibility of including external magnetic field in analysis

Abstract

The asymmetric tetrahedron is composed by all edges of tetrahedron represented by Ising interaction except one, which has a Heisenberg type interaction. This asymmetric tetrahedron is arranged connecting a vertex which edges are only Ising type interaction to another vertex with same structure of another tetrahedron. The process is replicated and this kind of lattice we call the asymmetric Ising-Heisenberg chain. We have studied the ground state phase diagram for this kind of models. Particularly we consider two situations in the Heisenberg-type interaction, (i) The asymmetric tetrahedral spin(1/2,1/2) Ising-XYZ chain, and (ii) the asymmetric tetrahedral spin-(1/2,1) Ising-XXZ chain, where we have found a rich phase diagram and a number of multicritical points. Additionally we have also studied their thermodynamics properties and the correlation function, using the decorated transformation. We have mapped the asymmetric tetrahedral Ising-Heisenberg chain in an effective Ising chain, and we have also concluded that it is possible to evaluate the partition function including a longitudinal external magnetic field.