Spin disordered state of the triangular lattice antiferromagnet NiGa$_{2}$S$_{4}$

ORAL

Abstract

We have recently found a spin disordered state in two dimensions in NiGa$_{2}$S$_{4}$, a bulk insulating antiferromagnet on a triangular lattice.Despite strong antiferromagnetic interactions of $\sim $ 80 K, no magnetic long-range order has been observed down to 0.35 K where we instead find nano-scale quasi-static correlation. The spin disordered state appears on cooling through highly degenerate states with an entropy plateau, and exhibits gapless linearly dispersive modes, suggesting coherence beyond the two-spin correlation length. A possible ground state will be discussed.

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Authors

  • Satoru Nakatsuji

  • Yusuke Nambu

  • Hiroshi Tonomura

  • Osamu Sakai

    Department of Physics, Kyoto University, Kyoto 606-8502, Japan

  • Seth Jonas

  • Collin Broholm

    Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA, Johns Hopkins University, Department of Physics and Astronomy, Johns Hopkins University

  • Hirokazu Tsunetsugu

    Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan

  • Yiming Qiu

    NIST Center for Neutron Research, NIST, Gaithersburg, MD 20899, USA

  • Yoshiteru Maeno

    Department of Physics, Kyoto University, Department of Physics, Kyoto University, Kyoto 606-8502, Japan, Kyoto University, Kyoto, Japan, Kyoto University, Japan, Kyoto University