Anomalous Temperature Dependence of Quantum Correction to the Conductivity of Magnetic Topological Insulators

TL;DR

This paper explains the unusual temperature dependence of quantum conductivity corrections in magnetic topological insulators by linking Berry phase variations to electron decoherence, revealing non-monotonic behavior at low temperatures.

Contribution

It introduces a mechanism where bulk magnetization induces a tiny surface electron mass, affecting Berry phase and phase coherence, leading to anomalous temperature effects in conductivity.

Findings

Quantum correction to conductivity shows non-monotonic temperature dependence.

Berry phase variation influences quantum interference in topological surface states.

Decoherence mechanisms are linked to surface electron mass induced by bulk magnetization.

Abstract

Quantum transport in magnetic topological insulators reveals the strong interplay between the magnetism and topology of electronic band structures. A recent experiment on magnetically doped topological insulator Bi2Se3 thin films showed the anomalous temperature dependence of the magnetoconductivity while their field dependence presents a clear signature of weak anti-localization [Tkac et al., Phys. Rev. Lett. 123, 036406(2019)]. Here we demonstrate that the tiny mass of the surface electrons induced by the bulk magnetization leads to a temperature-dependent correction to the \pi Berry phase, and generates a decoherence mechanism to the phase coherence length of the surface electrons. As a consequence, the quantum correction to the conductivity can exhibit non-monotonic behavior by decreasing the temperature. This effect is attributed to the close relation of the Berry phase and quantum interference of the topological surface electrons in quantum topological materials.