ABSTRACT
The Z4 symmetry indicator is widely used to classify topological materials hosting inversion symmetry. We find orthorhombic Li2AuBi in space group Cmcm is a topological insulator with Z4=1 under no strain via first-principles calculations. Due to small band gaps in the kz = 0 plane, the band inversions can be selectively induced by moderate external strains to realize phases covering all values of Z4 = 1, 2, 3, and 0. Detailed Z4 phase diagrams are plotted under various moderate strains. The (001) surface states and their associated Fermi surfaces and spin textures are calculated. The topological surface states have different connectivities and different spin textures for the four different Z4 phases. The tunability of topological surface states via moderate strain suggests Li2AuBi as an attractive topological material for device applications.
