Localization and interaction effects of epitaxial Bi2Se3 bulk states in two-dimensional limit

Quantum interferenceeffects and electron-electron interactions are found to play an important role in two-dimensional (2D) bulk transport of topological insulator (TI)thin films, which were previously considered as 2D electron gas (2DEG) and explained on basis of Hikami-Larkin-Nagaoka formula and Lee-Ramakrishnantheory. The distinct massive Dirac-typeband structure of the TI bulk state gives rise to quantum corrections toconductivity due to interference and interactioneffects, which are quite different from that of a 2DEG. We interpret the experimental findings employing Lu-Shentheory particularly derived for the TI system in the 2D limit. Thesurface and the bulkconductions are identified based on slopes of logarithmic temperature-dependentconductivities withmagnetic fields. The perpendicular fieldmagnetoresistance is analyzed considering suppression of weak antilocalization/localization of the surface/bulk electrons by the applied field. We propose correspondingtheoretical models to explain the parallel and tilted fieldmagnetoresistance. Theeffect of theband structure is found to be crucial for an accurate explanation of the magnetotransport results in the TIthin film.

Source: Journal of Applied Physics - October 24, 2016 Category: Physics Authors: Rik Dey, Anupam Roy, Tanmoy Pramanik, Samaresh Guchhait, Sushant Sonde, Amritesh Rai, Leonard F. Register and Sanjay K. Banerjee Source Type: research