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arXiv · 2306.08624

Multipolar spin liquid in an exactly solvable model for $j_\mathrm{eff} = \frac{3}{2}$ moments

Vanuildo S. de Carvalho·Hermann Freire·Rodrigo G. Pereira
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Abstract

We study an exactly solvable model with bond-directional quadrupolar and octupolar interactions between spin-orbital entangled $j_{\mathrm{eff}} = \frac{3}{2}$ moments on the honeycomb lattice. We show that this model features a multipolar spin liquid phase with gapless fermionic excitations. In the presence of perturbations that break time-reversal and rotation symmetries, we find Abelian and non-Abelian topological phases in which the Chern number evaluates to $0$, $\pm 1$, and $\pm 2$. We also investigate quantum phase transitions out of the multipolar spin liquid using a parton mean-field approach and orbital wave theory. In the regime of strong integrability-breaking interactions, the multipolar spin liquid gives way to ferroquadrupolar-vortex and antiferro-octupolar ordered phases that harbor a hidden spin-$\frac{1}{2}$ Kitaev spin liquid. Our work unveils mechanisms for unusual multipolar orders and quantum spin liquids in Mott insulators with strong spin-orbit coupling.

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Vanuildo S. de Carvalho, Hermann Freire, Rodrigo G. Pereira. 2023-06-14. Multipolar spin liquid in an exactly solvable model for $j_\mathrm{eff} = \frac{3}{2}$ moments. https://doi.org/10.1103/physrevb.108.094418

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