Second-order topological insulators and superconductors with an order-two crystalline symmetry
Second-order topological insulators and superconductors with an order-two crystalline symmetry
Second-order topological insulators and superconductors have a gapped excitation spectrum in bulk and along boundaries, but protected zero modes at corners of a two-dimensional crystal or protected gapless modes at hinges of a three-dimensional crystal. A second-order topological phase can be induced by the presence of a bulk crystalline symmetry. …