Electronic and topological properties of Sn1-xInxTe

The electronic and topological properties of Sn1-xInxTe have been investigated based on first principles calculations. Sn1-xInxTe presents inverted bands at the L point, but the number of inverted bands depends on the In x composition. Nevertheless the computed mirror Chern number is always n(M) = -2 for all In concentrations studied here. Pairs of topologically protected states on the (001) surface of Sn1-xInxTe with +/- i mirror eigenvalues have been identified. The character of these topological states is affected by In dopant as compared to the parent topological crystalline insulator SnTe. As the In content x increases, the Dirac crossing point moves further away from the L point, and the Fermi velocity of the topological states increases significantly. Also we verify that a hole to electron carrier-like transition takes place at x = 0.25 due to depopulation of the In-5s orbital.Sn1-xInxTe is a superconductor, there is a co-existence of topological states protected by mirror symmetry on the surface with superconductivity in the bulk.