Impurity effect on weak anti-localization in the topological insulator Bi2Te3

TL;DR

This study investigates how impurities affect weak anti-localization in Bi2Te3 topological insulator thin films, revealing robustness against non-magnetic impurities and sensitivity to magnetic impurities that disrupt topological surface states.

Contribution

It demonstrates the impurity-dependent behavior of weak anti-localization in Bi2Te3, showing magnetic impurities quench WAL by destroying the surface state's Berry phase.

Findings

WAL is robust against non-magnetic Au impurities.

Magnetic Fe impurities quench WAL by destroying the Berry phase.

A crossover from symplectic to unitary class is observed with Fe impurities.

Abstract

We study weak anti-localization (WAL) effect in topological insulator Bi2Te3 thin films at low temperatures. Two-dimensional WAL effect associated with surface carriers is revealed in the tilted magnetic field dependence of magneto-conductance. Our data demonstrates that the observed WAL is robust against deposition of non-magnetic Au impurities on the surface of the thin films. But it is quenched by deposition of magnetic Fe impurities which destroy the pi Berry's phase of the topological surface states. The magneto-conductance data of a 5 nm Bi2Te3 film suggests that a crossover from symplectic to unitary classes is observed with the deposition of Fe impurities.