Heat Transport in Herbertsmithite: Can a Quantum Spin Liquid Survive Disorder?

Y. Y. Huang; Y. Xu; Le Wang; C. C. Zhao; C. P. Tu; J. M. Ni; L. S. Wang; B. L. Pan; Ying Fu; Zhanyang Hao; Cai Liu; Jia-Wei Mei; S. Y. Li

doi:10.1103/physrevlett.127.267202

arXiv · 2105.14749

Heat Transport in Herbertsmithite: Can a Quantum Spin Liquid Survive Disorder?

Y. Y. Huang·Y. Xu·Le Wang·C. C. Zhao·C. P. Tu·J. M. Ni·L. S. Wang·B. L. Pan·Ying Fu·Zhanyang Hao·Cai Liu·Jia-Wei Mei·S. Y. Li

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Abstract

Arguably the most favorable situation for spins to enter the long-sought quantum spin liquid (QSL) state is when they sit on a kagome lattice. No consensus has been reached in theory regarding the true ground state of this promising platform. The experimental efforts, relying mostly on one archetypal material ZnCu$_3$(OH)$_6$Cl$_2$, have also led to diverse possibilities. Apart from subtle interactions in the Hamiltonian, there is the additional degree of complexity associated with disorder in the real material ZnCu$_3$(OH)$_6$Cl$_2$ that haunts most experimental probes. Here we resort to heat transport measurement, a cleaner probe in which instead of contributing directly, the disorder only impacts the signal from the kagome spins. For ZnCu$_3$(OH)$_6$Cl$_2$ and a related QSL candidate Cu$_3$Zn(OH)$_6$FBr, we observed no contribution by any spin excitation nor any field-induced change to the thermal conductivity. These results impose different constraints on various scenarios about the ground state of these two kagome compounds: while a gapped QSL, or certain quantum paramagnetic state other than a QSL, is compatible with our results, a gapless QSL must be dramatically modified by the disorder so that gapless spin excitations are localized.

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Y. Y. Huang, Y. Xu, Le Wang, C. C. Zhao, C. P. Tu, J. M. Ni, L. S. Wang, B. L. Pan, Ying Fu, Zhanyang Hao, Cai Liu, Jia-Wei Mei, S. Y. Li. 2021-05-31. Heat Transport in Herbertsmithite: Can a Quantum Spin Liquid Survive Disorder?. https://doi.org/10.1103/physrevlett.127.267202

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