Weak antilocalization and electron-electron interaction in coupled multiple-channel transport in a Bi$_2$Se$_3$ thin film

TL;DR

This study investigates quantum transport phenomena in a 10 nm Bi$_2$Se$_3$ thin film, revealing weak antilocalization, electron-electron interactions, and coupled multiple-channel conduction, with temperature-dependent phase coherence and conductivity behaviors.

Contribution

It provides new insights into coupled topological surface and bulk states in Bi$_2$Se$_3$ thin films, highlighting their quantum corrections and interaction effects at low temperatures.

Findings

Weak antilocalization observed and analyzed.

Electron-electron interactions dominate quantum corrections.

Transport occurs via coupled multiple channels.

Abstract

Electron transport properties of a topological insulator Bi$_2$Se$_3$ thin film are studied in Hall-bar geometry. The film with a thickness of 10 nm is grown by van der Waals epitaxy on fluorophlogopite mica and Hall-bar devices are fabricated from the as-grown film directly on the mica substrate. Weak antilocalization and electron-electron interaction effects are observed and analyzed at low temperatures. The phase-coherence length extracted from the measured weak antilocalization characteristics shows a strong power-law increase with decreasing temperature and the transport in the film is shown to occur via coupled multiple (topological surface and bulk states) channels. The conductivity of the film shows a logarithmically decrease with decreasing temperature and thus the electron-electron interaction plays a dominant role in quantum corrections to the conductivity of the film at low temperatures.