Thermal Canting of Spin-Bond Order

TL;DR

This paper investigates how finite temperatures influence spin and bond correlations in the quantum compass model, revealing thermal canting as an experimental signature of spin-bond anisotropy.

Contribution

It introduces a coupled mean field theory explaining thermal canting based on quantum critical properties of crossed Ising chains.

Findings

Finite temperatures cant the spin and space correlations.

Temperature can reorient spin correlations between orthogonal directions.

Thermal canting serves as an experimental signature of spin-bond anisotropy.

Abstract

Magnetism arising from coupled spin and spatial degrees of freedom underlies the properties of a broad array of physical systems. We study here the interplay between correlations in spin and space for the quantum compass model in a finite external field, using quantum Monte Carlo methods. We find that finite temperatures cant the spin and space (bond) correlations, with increasing temperature even reorienting spin correlations between orthogonal spatial directions. We develop a coupled mean field theory to understand this effect in terms of the underlying quantum critical properties of crossed Ising chains in transverse fields and an effective field that weakens upon increasing temperature. Thermal canting offers an experimental signature of spin-bond anisotropy.