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Density functional study of BiSbTeSe 2 topological insulator thin films
Author(s) -
Mohammadpourrad Zahra,
Abolhassani Mohammadreza
Publication year - 2017
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201700146
Subject(s) - topological insulator , band gap , thin film , condensed matter physics , surface states , density functional theory , materials science , penetration depth , topology (electrical circuits) , surface (topology) , physics , nanotechnology , optics , quantum mechanics , geometry , mathematics , combinatorics
In this work, using density functional theory calculations, we have investigated the band topology of bulk BiSbTeSe 2 and its thin film electronic properties in several thicknesses. It is one member of the quaternary compounds Bi 2– x Sb x Te 3– y Se y (BSTS) with the best intrinsic bulk insulating behavior. Based on our calculations we have found that a band inversion at Γ‐point is induced when spin–orbit coupling is turned on, with an energy gap of about 0.318 eV. The film thickness has an effect on the surface states such that a gap opens at Dirac point in 6 quintuple‐layers film and with decrease in thickness, the magnitude of the gap increases. The atomic contributions have been mapped out for the first few layers of thin films to demonstrate the surface states. The relative charge density has been calculated layer‐wise and the penetration depth of the surface states into the bulk region is found to be about 2.5–3.5 quintuple layers, depending on the termination species of thin films.