Universal scaling of the heat capacity in a quantum spin liquid state of 1T-TaS<sub>2</sub>
ORAL
Abstract
To elucidate the nature of quantum spin liquid (QSL), it is important to understand the effect of randomness on QSL. Here, we have investigated the low energy excitations on pure, Se-substituted and electron-irradiated 1T-TaS2, a QSL candidate material with spin-1/2 on a triangular lattice[1, 2], by measuring low-temperature thermal conductivity and heat capacity. Finite residual linear terms of thermal conductivity, κ/T(T→0), in pure 1T-TaS2 indicates the presence of itinerant gapless excitations. The magnetic contribution of the heat capacity of 1T-TaS2 and 1T-TaS2−xSex well obeys a universal scaling relation, consistent with a theory that assumes the presence of localized orphan spins forming random singlets[3]. These results capture a microscopic picture of the QSL, in which localized orphan spins induced by disorder are surrounded by itinerant spinon that forms Fermi surface. On the other hand, electron irradiation in 1T-TaS2, which introduces strong quenched disorders in Ta-layers, changes the scaling function dramatically, suggesting a possible new state of spin liquid.
[1] K. T. Law, et al., PNAS 110, 6996-7000 (2017).
[2] M. Klanjsek, et al., Nature Physics 13, 1130 (2017).
[3] I. Kimchi, et al., Nature Communication 9, 4367 (2018).
[4] H. Murayama, et al., arXiv:1909.00583.
[1] K. T. Law, et al., PNAS 110, 6996-7000 (2017).
[2] M. Klanjsek, et al., Nature Physics 13, 1130 (2017).
[3] I. Kimchi, et al., Nature Communication 9, 4367 (2018).
[4] H. Murayama, et al., arXiv:1909.00583.
–
Presenters
-
Hinako Murayama
- Physics, Kyoto University