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

## TL;DR

This study revisits the quantum spin liquid candidate EtMe3Sb[Pd(dmit)2]2, revealing no magnetic field-dependent thermal conductivity despite a finite specific heat, challenging previous claims of mobile gapless excitations like spinons.

## Contribution

The paper provides new ultralow-temperature thermal conductivity data showing absence of magnetic thermal transport, prompting a reassessment of the ground state of the material.

## Key findings

- Finite specific heat linear term observed
- No residual linear thermal conductivity detected
- Thermal conductivity unaffected by magnetic field

## 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 $et$ $al.$, 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 $et$ $al.$ 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.