The effects of pressure on a quantum spin liquid are investigated in an organic Mott insulator κ-(ET)2Ag2(CN)3 with a spin-1/2 triangular lattice. The application of negative chemical pressure to κ-(ET)2Cu2(CN)3, which is a well-known sister Mott insulator, allows for extensive tuning of antiferromagnetic exchange coupling, with J/kB=175−310 K, under hydrostatic pressure. Based on 13C nuclear magnetic resonance measurements under pressure, we uncover universal scaling in the static and dynamic spin susceptibilities down to low temperatures ∼0.1kBT/J. The persistent fluctuations and residual specific heat coefficient are consistent with the presence of gapless low-lying excitations. Our results thus demonstrate fundamental finite-temperature properties of quantum spin liquid in a wide parameter range.
@article{arxiv.1604.01460,
title = {Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice $\kappa$-(ET)$_2$Ag$_2$(CN)$_3$},
author = {Yasuhiro Shimizu and Takaaki Hiramatsu and Mitsuhiko Maesato and Akihiro Otsuka and Hideki Yamochi and Akihiro Ono and Masayuki Itoh and Makoto Yoshida and Masashi Takigawa and Yukihiro Yoshida and Gunzi Saito},
journal= {arXiv preprint arXiv:1604.01460},
year = {2016}
}