An ab initio investigation of BiSe topological insulator deposited on amorphous SiO
arXiv:1608.08195 · doi:10.1088/1361-648X/29/4/045302
Abstract
We use first-principles simulations to investigate the topological properties of BiSe thin films deposited on amorphous SiO2, BiSe/a-SiO, which is a promising substrate for topological insulator (TI) based device applications. The BiSe films are bonded to a-SiO mediated by van der Waals interactions. Upon interaction with the substrate, the BiSe topological 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 BiSe quintuple 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 BiSe QLs, and (ii) by deformation of the QL in contact with the a-SiO substrate. We also investigate the role played by oxygen vacancies (V) on the a-SiO, which increases the energy splitting between the two Dirac-like cones. Finally, by mapping the electronic structure of BiSe/a-SiO, we found that the a-SiO surface states, even upon the presence of V, play a minor role on gating the electronic transport properties of BiSe.
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