title: An ab initio investigation of Bi2Se3topological insulator deposited on amorphous SiO2.
abstract: We use first-principles simulations to investigate the topological properties of Bi2Se3thin films deposited on amorphous SiO2, Bi2Se3/a-SiO2, which is a promising substrate for topological insulator (TI) based device applications. The Bi2Se3films are bonded to a-SiO2mediated by van der Waals interactions. Upon interaction with the substrate, the Bi2Se3topological surface and interface states remain present, however the degeneracy between the Dirac-like cones is broken. The energy separation between the two Dirac-like cones increases with the number of Bi2Se3quintuple layers (QLs) deposited on the substrate. Such a degeneracy breaking is caused by (i) charge transfer from the TI to the substrate and charge redistribution along the Bi2Se3QLs, and (ii) by deformation of the QL in contact with the a-SiO2substrate. We also investigate the role played by oxygen vacancies ([Formula: see text]) on the a-SiO2, which increases the energy splitting between the two Dirac-like cones. Finally, by mapping the electronic structure of Bi2Se3/a-SiO2, we found that the a-SiO2surface states, even upon the presence of [Formula: see text], play a minor role on gating the electronic transport properties of Bi2Se3.
authors.affiliation: Departamento de Física, Universidade Federal de Lavras, C.P. 3037, 37200-000, Lavras, MG, Brazil.
authors.forename: I S S
authors.initials: IS
authors.lastname: de Oliveira
authors.forename: W L
authors.initials: WL
authors.lastname: Scopel
authors.forename: R H
authors.initials: RH
authors.lastname: Miwa