Absence of magnetic thermal conductivity in the quantum spin liquid candidate YbMgGaO4

Abstract

We present the ultra-low-temperature specific heat and thermal conductivity measurements on the single crystals of YbMgGaO${}_4$, which was recently argued to be a promising candidate for quantum spin liquid (QSL). In the zero magnetic field, a large magnetic contribution of specific heat is observed, and exhibits a power-law temperature dependence ($C_m\sim T^{0.74}$). On the contrary, we do not observed any significant contribution of thermal conductivity from magnetic excitations. In magnetic fields $H\ge$ 6 T, the exponential $T$-dependence of $C_m$ and the enhanced thermal conductivity indicate a magnon gap of the fully-polarized state. The absence of magnetic thermal conductivity at the zero field in this QSL candidate puts a strong constraint on the theories of its ground state.

6 pages, 3 figures, accepted for publication in Physical Review Letters

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Cited by in corpus (5)

• Experimental identification of quantum spin liquids
• Crystalline Electric Field Randomness in the Triangular Lattice Spin-Liquid YbMgGaO${}_4$
• Rearrangement of uncorrelated valence bonds evidenced by low-energy spin excitations in YbMgGaO4
• Heat transport study of the spin liquid candidate 1T-TaS2
• Spinon magnetic resonance of quantum spin liquids