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arXiv · 1604.01460

Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice $κ$-(ET)$_2$Ag$_2$(CN)$_3$

Yasuhiro Shimizu·Takaaki Hiramatsu·Mitsuhiko Maesato·Akihiro Otsuka·Hideki Yamochi·Akihiro Ono·Masayuki Itoh·Makoto Yoshida·Masashi Takigawa·Yukihiro Yoshida·Gunzi Saito
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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 $J/k_{\rm B} = 175 - 310$ 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 $\sim 0.1k_{\rm B}T/J$. The persistent fluctuations and residual specific heat coefficient are consistent with the presence of gapless low-lying excitations. Our results thus demonstrate fundamental finite-temperature properties of quantum spin liquid in a wide parameter range.

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Yasuhiro Shimizu, Takaaki Hiramatsu, Mitsuhiko Maesato, Akihiro Otsuka, Hideki Yamochi, Akihiro Ono, Masayuki Itoh, Makoto Yoshida, Masashi Takigawa, Yukihiro Yoshida, Gunzi Saito. 2016-09-01. Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice $κ$-(ET)$_2$Ag$_2$(CN)$_3$. https://doi.org/10.1103/physrevlett.117.107203

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