title: Topological phase transitions of (BixSb1-x)2Se3 alloys by density functional theory.
abstract: We have performed an ab initio total energy investigation of the topological phase transition, and the electronic properties of topologically protected surface states of (BixSb1-x)2Se3 alloys. In order to provide an accurate alloy concentration for the phase transition, we have considered the special quasirandom structures to describe the alloy system. The trivial → topological transition concentration was obtained by (i) the calculation of the band gap closing as a function of Bi concentration (x), and (ii) the calculation of the Z2 topological invariant number. We show that there is a topological phase transition, for x around 0.4, verified for both procedures (i) and (ii). We also show that in the concentration range 0.4 < x < 0.7, the alloy does not present any other band at the Fermi level besides the Dirac cone, where the Dirac point is far from the bulk states. This indicates that a possible suppression of the scattering process due to bulk states will occur.
authors.affiliation: Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970, São Paulo, SP, Brazil.
authors.forename: L B
authors.initials: LB
authors.lastname: Abdalla
authors.forename: E
authors.initials: E
authors.lastname: Padilha José
authors.forename: T M
authors.initials: TM
authors.lastname: Schmidt
authors.forename: R H
authors.initials: RH
authors.lastname: Miwa
authors.forename: A
authors.initials: A
authors.lastname: Fazzio