Surface versus bulk state in topological insulator Bi2Se3 under environmental disorder

TL;DR

This study investigates how environmental disorder affects the surface and bulk electronic states in Bi2Se3 topological insulator thin films, revealing that bulk states are sensitive while surface states are robust.

Contribution

It provides experimental evidence distinguishing the robustness of surface versus bulk states in Bi2Se3 under environmental disorder.

Findings

Bulk states are sensitive to environmental disorder.

Surface states remain robust despite environmental disorder.

Transport measurements differentiate surface and bulk state behaviors.

Abstract

Topological insulators (TIs) are predicted to be composed of an insulating bulk state along with conducting channels on the boundary of the material. In Bi2Se3, however, the Fermi level naturally resides in the conduction band due to intrinsic doping by selenium vacancies, leading to metallic bulk states. In such non-ideal TIs it is not well understood how the surface and bulk states behave under environmental disorder. In this letter, based on transport measurements of Bi2Se3 thin films, we show that the bulk states are sensitive to environmental disorder but the surface states remain robust.