Absence of Magnetic Thermal Conductivity in the Quantum Spin-Liquid Candidate YbMgGaO4

ORAL

Abstract

We present the ultralow-temperature specific heat and thermal conductivity measurements on single crystals of YbMgGaO4, which was recently argued to be a promising candidate for a quantum spin liquid (QSL). In a zero magnetic field, a large magnetic contribution of specific heat is observed, and exhibits a power-law temperature dependence (Cm ∼ T0.74). On the contrary, we do not observe any significant contribution of thermal conductivity from magnetic excitations. In magnetic fields H ≥ 6 T, the exponential T dependence of Cm and the enhanced thermal conductivity indicate a magnon gap of the fully polarized state. More crucially, from ultralow-temperature a.c. susceptibility measurements, we find evidence for a spin-glass ground state with the observation of frequency-dependent peaks around 0.1 K. Therefore, we conclude that instead of a QSL, the ground state of YbMgGaO4 is likely a disorder-induced spin glass [1, 2].
[1] Y. Xu, et al., Physical Review Letters 117, 267202 (2016).
[2] Z. Ma, et al., arXiv:1709.00256.

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Presenters

  • Yang Xu

    State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University

Authors

  • Yang Xu

    State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University

  • Jun Zhang

    State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University

  • Yuesheng Li

    Department of Physics, Renmin University of China

  • Yunjie Yu

    Fudan Univ, State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Fudan University

  • Xiaochen Hong

    State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University

  • Zhen Ma

    National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University

  • Jinsheng Wen

    National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing Univ, Department of Physics, Nanjing University, Nanjing University

  • Qingming Zhang

    Department of Physics, Renmin University of China

  • Shiyan Li

    University of Sherbrooke, Fudan Univ, State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, State Key Laboratory of Surface Physics and Laboratory of Advanced Materials, Department of Physics, Fudan University, Fudan University