Strong surface scattering in ultrahigh mobility Bi2Se3 topological insulator crystals

Abstract

While evidence of a topologically nontrivial surface state has been identified in surface-sensitive measurements of Bi2Se3, a significant experimental concern is that no signatures have been observed in bulk transport. In a search for such states, nominally undoped single crystals of Bi2Se3 with carrier densities approaching 10^16 cm^-3 and very high mobilities exceeding 2 m^2 V^-1 s^-1 have been studied. A comprehensive analysis of Shubnikov de Haas oscillations, Hall effect, and optical reflectivity indicates that the measured electrical transport can be attributed solely to bulk states, even at 50 mK at low Landau level filling factor, and in the quantum limit. The absence of a significant surface contribution to bulk conduction demonstrates that even in very clean samples, the surface mobility is lower than that of the bulk, despite its topological protection.

4 pgs, 4 figs; title changed, minor text revision, references updated

References in corpus (4)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Topological Surface States Protected From Backscattering by Chiral Spin Texture
• Bulk Fermi surface coexistence with Dirac surface state in Bi${}_2$Se${}_3$: a comparison of photoemission and Shubnikov-de Haas measurements

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• Nonlinear optical probe of tunable surface electrons on a topological insulator
• Ultrafast carrier and phonon dynamics in Bi2Se3 crystals
• Spatially resolved femtosecond pump-probe study of topological insulator Bi2Se3
• Electron-phonon scattering in topological insulators
• Terahertz Kerr and Reflectivity Measurements on the Topological Insulator Bi2Se3
• Proposal for a Topological Plasmon Spin Rectifier
• Signatures of Wigner molecule formation in interacting Dirac fermion quantum dots