title: Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice κ-(ET)_{2}Ag_{2}(CN)_{3}.
abstract: The effects of pressure on a quantum spin liquid are investigated in an organic Mott insulator κ-(ET)_{2}Ag_{2}(CN)_{3} with a spin-1/2 triangular lattice. The application of negative chemical pressure to κ-(ET)_{2}Cu_{2}(CN)_{3}, which is a well-known sister Mott insulator, allows for extensive tuning of antiferromagnetic exchange coupling, with J/k_{B}=175-310  K, under hydrostatic pressure. Based on ^{13}C nuclear magnetic resonance measurements under pressure, we uncover universal scaling in the static and dynamic spin susceptibilities down to low temperatures ∼0.1k_{B}T/J. The persistent fluctuations and residual specific heat coefficient are consistent with the presence of gapless low-lying excitations. Our results thus demonstrate the fundamental finite-temperature properties of a quantum spin liquid in a wide parameter range.
authors.affiliation: Department of Physics, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Faculty of Agriculture, Meijo University, Tempaku-ku, Nagoya 468-8502, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hiramatsu
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Maesato
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.|Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Otsuka
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.|Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamochi
authors.affiliation: Department of Physics, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ono
authors.affiliation: Department of Physics, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Itoh
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Takigawa
authors.affiliation: Faculty of Agriculture, Meijo University, Tempaku-ku, Nagoya 468-8502, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yoshida
authors.affiliation: Faculty of Agriculture, Meijo University, Tempaku-ku, Nagoya 468-8502, Japan.|Toyota Physical and Chemical Research Institute, Nagakute, Aichi 480-1192, Japan.
authors.forename: Gunzi
authors.initials: G
authors.lastname: Saito