Thickness-independent transport channels in topological insulator Bi2Se3 thin films

Namrata Bansal; Yong Seung Kim; Matthew Brahlek; Eliav Edrey; Seongshik Oh

doi:10.1103/PhysRevLett.109.116804

Thickness-independent transport channels in topological insulator Bi2Se3 thin films

Materials Science 2012-09-14 v3

Authors: Namrata Bansal , Yong Seung Kim , Matthew Brahlek , Eliav Edrey , Seongshik Oh

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Abstract

With high quality topological insulator (TI) Bi2Se3 thin films, we report thickness-independent transport properties over wide thickness ranges. Conductance remained nominally constant as the sample thickness changed from 256 to ~8 QL (QL: quintuple layer, 1 QL = ~1 nm). Two surface channels of very different behaviors were identified. The sheet carrier density of one channel remained constant at ~3.0 x 10^13 cm^-2 down to 2 QL, while the other, which exhibited quantum oscillations, remained constant at ~8 x 10^12 cm^-2 only down to ~8 QL. The weak antilocalization parameters also exhibited similar thickness-independence. These two channels are most consistent with the topological surface states and the surface accumulation layers, respectively.

Keywords

topological insulator Bi2Se3 thin films thickness-independent transport surface channels quantum oscillations weak antilocalization surface accumulation layer

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@article{arxiv.1104.5709,
  title  = {Thickness-independent transport channels in topological insulator Bi2Se3 thin films},
  author = {Namrata Bansal and Yong Seung Kim and Matthew Brahlek and Eliav Edrey and Seongshik Oh},
  journal= {arXiv preprint arXiv:1104.5709},
  year   = {2012}
}

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To appear in Phys. Rev. Lett

Thickness-independent transport channels in topological insulator Bi2Se3 thin films

Abstract

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