Disorder-induced decoupled surface transport channels in thin films of doped topological insulators

Hanbum Park, Jimin Chae, Kwangsik Jeong, Hyejin Choi, Jaehun Jeong, Dasol Kim, Mann Ho Cho

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Nonideal topological insulator (TI) films in which the bulk states are not insulating due to unintentional doping exhibit strong surface-bulk coupling. Such surface-bulk coupling can further induce intersurface coupling that affects the electrical conductivity of the TI films through a quantum interference effect known as weak antilocalization. Increased understanding and control of intersurface coupling is therefore crucial for the use of TI-based quantum devices. In this report on the transport properties of doped Bi2Se3 films under perpendicular and parallel magnetic fields, we observe a crossover between coupled and decoupled surface channels that is mediated by intentional disorder controlled by a post-annealing process. The intentional disorder causes the surface state carriers to rapidly lose their quantum phase and coherence, and as a result, more disordered Bi2Se3 films exhibit a shorter penetration depth of the surface state into the bulk states and weaker intersurface coupling, even though stronger surface-bulk coupling is expected. In previous studies, the role of disorder has generally been considered by determining its effect on surface-bulk scattering, but our results indicate that the role of disorder must be considered as a source of decoherence.

Original languageEnglish
Article number045411
JournalPhysical Review B
Volume98
Issue number4
DOIs
Publication statusPublished - 2018 Jul 12

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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