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arXiv · 2005.14500

Topological second-order spin-3/2 liquids with hinge Fermi arcs

Y. X. Zhao·Y. Lu·Shengyuan A. Yang
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Abstract

We present an exactly solvable spin-3/2 model defined on a pentacoordinated three-dimensional graphite lattice, which realizes a novel quantum spin liquid with second-order topology. The exact solutions are described by Majorana fermions coupled to a background $\mathbb{Z}_2$ gauge field, whose ground-state flux configuration gives rise to an emergent off-centered spacetime inversion symmetry. The symmetry protects topologically nontrivial band structures for the Majorana fermions, particularly including nodal-line semimetal phases with twofold topological charges: the second Stiefel-Whitney number and the quantized Berry phase. The former leads to rich topological phenomena on the system boundaries. There are two nodal-line semimetal phases hosting hinge Fermi arcs located on different hinges, and they are separated by a critical Dirac semimetal state with surface helical Fermi arcs. In addition, we show that rich symmetry/topology can be explored in our model by simply varying the lattice or interaction arrangement. As an example, we discuss how to achieve a topological gapped phase with surface Dirac points.

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Y. X. Zhao, Y. Lu, Shengyuan A. Yang. 2020-05-29. Topological second-order spin-3/2 liquids with hinge Fermi arcs. https://arxiv.org/abs/2005.14500

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