Magnetic analogue of liquid-gas phase transition of water: case study of a spin-1/2 Ising-Heisenberg model on a diamond-decorated square lattice

TL;DR

This study explores a magnetic phase transition in a spin-1/2 Ising-Heisenberg model on a diamond-decorated square lattice, revealing a temperature-driven transition analogous to liquid-gas phase changes in water.

Contribution

It introduces a generalized decoration-iteration transformation to map the complex model to an effective Ising model, providing new insights into magnetic phase transitions.

Findings

Identified a temperature-driven phase transition between ferrimagnetic and monomer-dimer phases.

Analyzed magnetization, susceptibility, and specific heat near phase boundaries.

Mapped the model to an effective Ising model with temperature-dependent interactions.

Abstract

The spin-1/2 Ising-Heisenberg model on a diamond-decorated square lattice exhibits an intriguing temperature-driven phase transition in a magnetic field between a classical ferrimagnetic phase and a quantum monomer-dimer phase. A generalized decoration-iteration transformation accurately maps the considered model to an effective spin-1/2 Ising model on a square lattice with temperature-dependent effective interactions and field, whereby the effective field vanishes at the phase boundary separating the classical ferrimagnetic phase from the quantum monomer-dimer phase. Typical features of the magnetization, magnetic susceptibility and specific heat in the vicinity of discontinuous and continuous thermal phase transitions between the classical ferrimagnetic phase and the quantum monomer-dimer phase are elucidated.