Band bending at the surface of Bi2Se3 studied from first principles

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Abstract

The band bending (BB) effect on the surface of the second-generation topological insulators implies a serious challenge to design transport devices. The BB is triggered by the effective electric field generated by charged impurities close to the surface and by the inhomogeneous charge distribution of the occupied surface states (SSs). Our self-consistent calculations in the Korringa-Kohn-Rostoker framework showed that in contrast to the bulk bands, the spectrum of the SSs is not bent at the surface. In turn, it is possible to tune the energy level of the Dirac point via the deposited surface dopants. In addition, the electrostatic modifications induced by the charged impurities on the surface induce long range oscillations in the charge density. For dopants located beneath the surface, however, these oscillations become highly suppressed. Our findings are in good agreement with recent experiments, however, our results indicate that the concentration of the surface doping cannot be estimated from the energy shift of the Dirac cone within the scope of the effective continuous model for the protected SSs.

Original languageEnglish
Article number123011
JournalNew Journal of Physics
Volume17
Issue number12
DOIs
Publication statusPublished - Dec 7 2015

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Keywords

  • Dirac cone
  • band bending
  • topological insulator

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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