Screening effect in low dimension : role of dielectrics and substrates on electronic strucuture of 1- and 2-dimensional materials
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Authors
Jiang, Xueping
Issue Date
2014-08
Type
Electronic thesis
Thesis
Thesis
Language
ENG
Keywords
Physics
Alternative Title
Abstract
For TIs, the surface states could be influenced due to the underlying substrates. Using density functional method and spin-orbit coupling, the Dirac cones and the bands around them are studied. Graphene has been found to be a suitable substrate for topological insulators (TIs) in recent experiments. In our study, six quintuple layers (QLs) as well as just one QL were considered for Bi2Se3. When six QLs of Bi2Se3 are supported by a graphene substrate on either one or both sides, the Dirac cone of the TI is shifted below the Fermi energy and a small band gap of graphene is opened. In addition, the influence of the graphene substrate on the real space density of the topological surfaces states (TSS) is found to be negligible. The Dirac point of Bi2Se3 splits to two Dirac points when graphene is deposited on only one side. For one QL Bi2Se3 the electronic structure near the band gap was strongly perturbed due to the interaction with graphene orbitals. These results will be compared with other works of TIs on substrates and their impact on device properties will be discussed in detail.
Description
August 2014
School of Science
School of Science
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY