Controlling and distinguishing electronic transport of topological and trivial surface states in a topological insulator

Abstract

Topological insulators (TI), with characteristic Dirac-fermion topological surface states (TSS), have emerged as a new class of electronic materials with rich potentials for both novel physics and device applications. However, a major challenge with realistic TI materials is to access, distinguish and manipulate the electronic transport of TSS often obscured by other possible parallel conduction channels that include the bulk as well as a two-dimensional electron gas (2DEG) formed near the surface due to bending of the bulk bands. Such a (Schrodinger-fermion) 2DEG represents topologically-trivial surface states, whose coexistence with the TSS has been revealed by angle resolved photoemission spectroscopy. Here we show that simple manipulations of surface conditions can be used to access and control both types of surface states and their coexistence in bulk-insulating Bi2Te2Se, whose surface conduction is prominently manifested in temperature dependent resistance and nonlocal transport. The trivial 2DEG and TSS can both exhibit clear Shubnikov-de Haas oscillations in magnetoresistance, with different Berry phases ~0 and ~pi that distinguish their different topological characters. We also report a deviation from the typical weak antilocalization behavior, possibly due to high mobility TSS. Our study enables distinguishing, controlling and harnessing electronic transport of TI surface carriers with different topological natures.

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• Topological Insulators
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Cited by in corpus (5)

• Opposite current-induced spin polarizations in bulk-metallic Bi2Se3 and bulk-insulating Bi2Te2Se topological insulator thin flakes
• Electrical spin injection into graphene from a topological insulator in a van der Waals heterostructure
• Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films
• Large Enhancement of Electronic Thermal Conductivity and Lorenz Number in Topological Insulator Bi2Te2Se Thin Films
• Tuning Chemical Potential in the Dirac Cone by Compositional Engineering