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arXiv · 2008.06544

Reinvestigation of the homogeneous spin model in YbMgGaO$_4$

Shaozhi Li
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Abstract

Motivated by a recent inelastic neutron scattering experiment on $\mathrm{YbMgGaO}_4$ \cite{William2019}, we reinvestigate the homogeneous spin model on the triangular lattice. Using the cluster mean-field theory, we study the phase diagram and the magnetic-field-induced phase transition. We find that the phase boundary between the stripe state and the $120^{\circ}$ antiferromagnetic state is broadened by the magnetic field, leading to a field-induced phase transition. This phase transition is suppressed by the next-nearest neighbor exchange interaction $J_2/J_1$ and vanishes as $J_2/J_1>0.13$. We find a parameter space at $J_2/J_1=0.1$, in which the field-induce transition can be achieved and the deviation of theoretical spin excitation energies from experimental data is only $5.4\%$. Our results imply that an effective homogeneous spin model still works in $\mathrm{YbMgGaO}_4$.

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Shaozhi Li. 2020-08-14. Reinvestigation of the homogeneous spin model in YbMgGaO$_4$. https://doi.org/10.1103/physrevb.103.104421

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