Spontaneous distortion in the spin-1/2 Ising-Heisenberg model on decorated planar lattices with a magnetoelastic coupling

TL;DR

This study investigates how magnetoelastic coupling influences quantum and classical phases in a spin-1/2 Ising-Heisenberg model on decorated lattices, revealing enhanced quantum effects and reduced critical temperatures due to lattice fluctuations.

Contribution

It introduces a detailed analysis of magnetoelastic effects in a decorated lattice model, highlighting the differential impact on quantum versus classical magnetic phases.

Findings

Quantum fluctuations are enhanced by lattice vibrations in the antiferromagnetic phase.

Lattice fluctuations significantly lower the critical temperature in the quantum phase.

Classical ferromagnetic phase remains unaffected by lattice vibrations.

Abstract

Magnetoelastic properties of the spin-1/2 Ising-Heisenberg model on doubly decorated planar lattices partially amenable to lattice vibrations are examined within the framework of the harmonic approximation and decoration-iteration transformation. It is shown that the mutual interplay between quantum spin fluctuations and local fluctuations of lattice spacings enhances typical quantum features like the quantum reduction of the magnetization in the ground state of the quantum antiferromagnetic phase, while it does not affect the ground-state behaviour of the classical ferromagnetic phase by no means. It also turns out that local fluctuations of lattice spacings are responsible for a much more pronounced reduction of the critical temperature in the quantum antiferromagnetic phase than in the classical ferromagnetic phase.