Absence of Magnetic Thermal Conductivity in the Quantum Spin-Liquid Candidate YbMgGaO<sub>4</sub>

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