Spinon heat transport in the three-dimensional quantum magnet PbCuTe$_2$O$_6$

TL;DR

This study demonstrates that the three-dimensional quantum magnet PbCuTe$_2$O$_6$ exhibits spinon-mediated heat transport consistent with a quantum spin liquid state, resilient against various external perturbations, confirming its intrinsic quantum disordered nature.

Contribution

It provides direct evidence of spinon heat transport in a 3D QSL candidate, establishing PbCuTe$_2$O$_6$ as a genuine quantum spin liquid material.

Findings

Sub-Kelvin thermal transport is dominated by charge-neutral fermionic excitations.

Spinon Fermi surface features are robust against magnetic field and sample quality.

PbCuTe$_2$O$_6$ exhibits intrinsic quantum spin liquid behavior.

Abstract

Quantum spin liquids (QSL) are novel phases of matter which remain quantum disordered even at the lowest temperature. They are characterized by emergent gauge fields and fractionalized quasiparticles. Here we show that the sub-Kelvin thermal transport of the three-dimensional $S=1/2$ hyper-hyperkagome quantum magnet PbCuTe$_2$O$_6$ is governed by a sizeable charge-neutral fermionic contribution which is compatible with the itinerant fractionalized excitations of a spinon Fermi surface. We demonstrate that this hallmark feature of the QSL state is remarkably robust against sample crystallinity, large magnetic field, and field-induced magnetic order, ruling out the imitation of QSL features by extrinsic effects. Our findings thus reveal the characteristic low-energy features of PbCuTe$_2$O$_6$ which qualify this compound as a true QSL material.