paper

Absence of magnetic thermal conductivity in the quantum spin liquid candidate EtMe3Sb[Pd(dmit)2]2 -- revisited

arXiv:1904.10395 · doi:10.1103/PhysRevLett.123.247204

Abstract

We present the ultralow-temperature specific heat and thermal conductivity measurements on single crystals of triangular-lattice organic compound EtMe $_{3}$ Sb[Pd(dmit) $_{2}$ ] $_{2}$ , which has long been considered as a gapless quantum spin liquid candidate. In specific heat measurements, a finite linear term is observed, consistent with the previous work [S. Yamashita $e t$ $a l .$ , Nat. Commun. {\bf 2}, 275 (2011)]. However, we do not observe a finite residual linear term in the thermal conductivity measurements, and the thermal conductivity does not change in a magnetic field of 6 Tesla. These results are in sharp contrast to previous thermal conductivity measurements on EtMe $_{3}$ Sb[Pd(dmit) $_{2}$ ] $_{2}$ [M. Yamashita $e t$ $a l .$ Science {\bf 328}, 1246 (2010)], in which a huge residual linear term was observed and attributed to highly mobile gapless excitations, likely the spinons of a quantum spin liquid. In this context, the true ground state of EtMe $_{3}$ Sb[Pd(dmit) $_{2}$ ] $_{2}$ has to be reconsidered.

6 pages, 4 figures