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arXiv · 1801.06941

Finite-temperature behavior of a classical spin-orbit-coupled model for $\textrm{YbMgGaO}_4$ with and without bond disorder

Edward Parker·Leon Balents
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Abstract

We present the results of finite-temperature classical Monte Carlo simulations of a strongly spin-orbit-coupled nearest-neighbor triangular-lattice model for the candidate $\mathrm{U}(1)$ quantum spin liquid $\mathrm{YbMgGaO}_4$ at large system sizes. We find a single continuous finite-temperature stripe-ordering transition with slowly diverging heat capacity that completely breaks the sixfold ground-state degeneracy, despite the absence of a known conformal field theory describing such a transition. We also simulate the effect of random-bond disorder in the model, and find that even weak bond disorder destroys the transition by fragmenting the system into very large domains -- possibly explaining the lack of observed ordering in the real material. The Imry-Ma argument only partially explains this fragility to disorder, and we extend the argument with a physical explanation for the preservation of our system's time-reversal symmetry even under a disorder model that preserves the same symmetry.

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Edward Parker, Leon Balents. 2018-05-11. Finite-temperature behavior of a classical spin-orbit-coupled model for $\textrm{YbMgGaO}_4$ with and without bond disorder. https://doi.org/10.1103/physrevb.97.184413

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