Abstract
We present ultralow-temperature thermal conductivity measurements on single crystals of the prototypical charge-density-wave material 1T-TaS2, which was recently argued to be a candidate for a quantum spin liquid. Our experiments show that the residual linear term of thermal conductivity at zero field is essentially zero, within experimental accuracy. Furthermore, the thermal conductivity is found to be insensitive to the magnetic field up to 9 T. These results clearly demonstrate the absence of itinerant magnetic excitations with fermionic statistics in bulk 1T-TaS2, and thus put a strong constraint on the theories of the ground state of this material.