Thickness-dependent bulk properties and weak antilocalization effect in topological insulator Bi 2 Se 3

By Yong Seung Kim, M. Brahlek, N. Bansal, Eliav Edrey, Gary A. Kapilevich, K. Iida, M. Tanimura, Y. Horibe, S. Cheong, Seongshik Oh. 2011

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We show that a number of transport properties in topological insulator (TI) Bi${}_{2}$Se${}_{3}$ exhibit striking thickness dependences over a range of up to five orders of thickness (3 nm--170 \ensuremath{\mu}m). Volume carrier density decreased with thickness, presumably due to diffusion-limited formation of selenium vacancies. Mobility increased linearly with thickness in the thin film regime and saturated in the thick limit. The weak antilocalization effect was dominated by a single two-dimensional channel over two decades of thickness. The sublinear thickness-dependence of the phase coherence length suggests the presence of strong coupling between the surface and bulk states.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/587378f6d01e7d52ed04023fba3f81aac9e4f63e