title: Tuning band inversion symmetry of buckled III-Bi sheets by halogenation.
abstract: First-principles calculations are employed to investigate structural, electronic and topological insulating properties of XBi (X = B, Al, Ga, and In) monolayers upon halogenation. It is known that Y-XBi (X = Ga, In, Tl; Y = F, Cl, Br, I) can originate inversion-asymmetric topological insulators with large bulk band gaps. Our results suggest that Y-XBi (X = B, Al; Y = F, Cl, Br, I) may also result in nontrivial topological insulating phases. Despite the lower atomic number of B and Al, the spin-orbit coupling opens a band gap of about 400 meV in Y-XBi (X = B, Al), exhibiting an unusual electronic behavior for practical applications in spintronics. The nature of the bulk band gap and Dirac-cone edge states in their nanoribbons depends on the group-III elements and Y chemical species. They lead to a chemical tunability, giving rise to distinct band inversion symmetries and exhibiting Rashba-type spin splitting in the valence band of these systems. These findings indicate that a large family of Y-XBi sheets can exhibit nontrivial topological characteristics, by a proper tuning, and open a new possibility for viable applications at room temperature.
authors.affiliation: Grupo de Física de Superfícies e Materiais, Instituto de Física, Universidade Federal da Bahia, Campus Universitário da Federação, 40170-115 Salvador, Bahia, Brazil. Department of Physics, Chemistry and Biology (IFM), Linköping University, 581 83 Linköping, Sweden.
authors.forename: R R Q
authors.initials: RR
authors.lastname: Freitas
authors.forename: F
authors.initials: F
authors.lastname: de Brito Mota
authors.forename: R
authors.initials: R
authors.lastname: Rivelino
authors.forename: C M C
authors.initials: CM
authors.lastname: de Castilho
authors.forename: A
authors.initials: A
authors.lastname: Kakanakova-Georgieva
authors.forename: G K
authors.initials: GK
authors.lastname: Gueorguiev