Classical spin liquids in stacked triangular lattice Ising antiferromagnets

TL;DR

This paper investigates classical spin-liquid behavior in multilayer triangular lattice Ising antiferromagnets with frustrated stacking, revealing a wide spin-liquid regime at low temperatures for frustrated stackings, unlike unfrustrated stacking.

Contribution

It introduces a combined Monte Carlo, height model, and renormalisation group approach to analyze spin-liquid regimes in frustrated multilayer Ising models, highlighting the effects of stacking frustration.

Findings

Spin-liquid regime is wide at low interlayer coupling in frustrated stackings.

Unfrustrated stacking does not exhibit a broad spin-liquid regime.

Strong intra- and inter-plane correlations occur without long-range order.

Abstract

We study Ising antiferromagnets that have nearest-neighbour interactions on multilayer triangular lattices with frustrated ($abc$ and $abab$) stacking, and make comparisons with the unfrustrated ($aaa$) stacking. If interlayer couplings are much weaker than in-plane ones, the paramagnetic phase of models with frustrated stackings has a classical spin-liquid regime at low temperature, in which correlations are strong both within and between planes, but there is no long-range order. We investigate this regime using Monte Carlo simulations and by mapping the spin models to coupled height models, which are treated using renormalisation group methods and an analysis of the effects of vortex excitations. The classical spin-liquid regime is parametrically wide at small interlayer coupling in models with frustrated stackings. By contrast, for the unfrustrated stacking there is no extended regime in which interlayer correlations are strong without three-dimensional order.