1T-TaS2 is a layered transition metal dichalgeonide with a very rich phase diagram. At T=180K it undergoes a metal to Mott insulator transition. Mott insulators usually display anti-ferromagnetic ordering in the insulating phase but 1T-TaS2 was never shown to order magnetically. In this letter we show that 1T-TaS2 has a large paramagnetic contribution to the magnetic susceptibility but it does not show any sign of magnetic ordering or freezing down to 20mK, as probed by μSR, possibly indicating a quantum spin liquid ground state. Although 1T-TaS2 exhibits a strong resistive behavior both in and out-of plane at low temperatures we find a linear term in the heat capacity suggesting the existence of a Fermi-surface, which has an anomalously strong magnetic field dependence.
@article{arxiv.1709.09440,
title = {Gapless excitations in the ground state of 1T-TaS$_2$},
author = {A. Ribak and I. Silber and C. Baines and K. Chashka and Z. Salman and Y. Dagan and A. Kanigel},
journal= {arXiv preprint arXiv:1709.09440},
year = {2017}
}