LAUSR

Determining the topological phases in crystalline systems requires a complete set of topological invariants, whose definition and evaluation is, in general, a complicated task. Symmetry-based indicators, such as the Fu-Kane formula for inversion-symmetric topological insulators, utilize the crystalline symmetry to define easy-to-compute topological invariants. These indicators can be generalized to extract the maximal information about the topology of the band structure and of the associated anomalous boundary states from data at the high-symmetry momenta only. Using the concept of relative topology, the authors show how to construct symmetry-based indicators for band superconductors.