Thermal Conductivity of the Quantum Spin Liquid Candidate EtMe_{3}Sb[Pd(dmit)_{2}]_{2}: No Evidence of Mobile Gapless Excitations

Autor: P. Bourgeois-Hope, F. Laliberté, E. Lefrançois, G. Grissonnanche, S. René de Cotret, R. Gordon, S. Kitou, H. Sawa, H. Cui, R. Kato, L. Taillefer, N. Doiron-Leyraud
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Physical Review X, Vol 9, Iss 4, p 041051 (2019)
Druh dokumentu: article
ISSN: 2160-3308
DOI: 10.1103/PhysRevX.9.041051
Popis: The thermal conductivity κ of the quasi-2D organic spin-liquid candidate EtMe_{3}Sb[Pd(dmit)_{2}]_{2} (dmit-131) was measured at low temperatures, down to 0.07 K. We observe a vanishingly small residual linear term κ_{0}/T, in κ/T vs T as T→0. This shows that the low-energy excitations responsible for the sizable residual linear term γ in the specific heat C, seen in C/T vs T as T→0, are localized. We conclude that there are no mobile gapless excitations in this spin-liquid candidate, in contrast with a prior study of dmit-131 that reported a large κ_{0}/T value [Yamashita et al., Science 328, 1246 (2010)SCIEAS0036-807510.1126/science.1188200]. Our study shows that dmit-131 is in fact similar to κ-(BEDT-TTF)_{2}Cu_{2}(CN)_{3}, another quasi-2D organic spin-liquid candidate where a vanishingly small κ_{0}/T and a sizable γ are seen. We attribute heat conduction in these organic insulators without magnetic order to phonons undergoing strong spin-phonon scattering, as observed in several other spin-liquid materials.
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