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arXiv · 2109.02664

Higher-order topological semimetals and nodal superconductors with an order-two crystalline symmetry

Sophia Simon·Max Geier·Piet W. Brouwer
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Abstract

Using a systematic relation between topological gapless phases in three dimensions and topological gapped phases in two dimensions, we identify four types of higher-order topological semimetals or nodal superconductors (HOTS), hosting (i) flat zero-energy "Fermi arcs" at crystal hinges, (ii) flat zero-energy hinge arcs coexisting with surface Dirac cones, (iii) chiral or helical hinge modes, or (iv) flat zero-energy hinge arcs connecting nodes only at finite momentum. Bulk-boundary correspondence relates the hinge states to the bulk topology protecting the nodal point or loop. We classify all HOTS for all tenfold-way classes with an order-two crystalline (anti-)symmetry, such as mirror, twofold rotation, or inversion.

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Sophia Simon, Max Geier, Piet W. Brouwer. 2021-09-06. Higher-order topological semimetals and nodal superconductors with an order-two crystalline symmetry. https://doi.org/10.1103/physrevb.106.035105

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