Evidence for a three-dimensional quantum spin liquid in PbCuTe$_{2}$O$_{6}$

TL;DR

This paper presents evidence that PbCuTe$_{2}$O$_{6}$ hosts a three-dimensional quantum spin liquid state, characterized by highly entangled spins with no static magnetism and fractional excitations, expanding the understanding of 3D spin liquids.

Contribution

It introduces a new three-dimensional lattice called hyper-hyperkagome in PbCuTe$_{2}$O$_{6}$, demonstrating its potential as a quantum spin liquid host through combined experimental and theoretical analysis.

Findings

No static magnetism detected in PbCuTe$_{2}$O$_{6}$

Presence of diffuse magnetic continua suggestive of fractional spinons

Evidence supports a three-dimensional quantum spin liquid state

Abstract

The quantum spin liquid (QSL) is a highly entangled magnetic state characterized by the absence of static magnetism in its ground state. Instead, the spins fluctuate in a highly correlated way down to the lowest temperatures. The QSL is very rare and is confined to a few specific cases where the interactions between the magnetic ions cannot be simultaneously satisfied (known as frustration). Lattices with magnetic ions in triangular or tetrahedral arrangements which interact via isotropic antiferromagnetic interactions can generate such a frustration. Three-dimensional isotropic spin liquids have mostly been sought in materials where the magnetic ions form pyrochlore or hyperkagome lattices. Here we present a three-dimensional lattice called the hyper-hyperkagome that enables spin liquid behaviour and manifests in the compound PbCuTe$_{2}$O$_{6}$. Using a combination of experiment and theory we show that this system exhibits signs of being a quantum spin liquid with no detectable static magnetism together with the presence of diffuse continua in the magnetic spectrum suggestive of fractional spinon excitations.