Influence of an anomalous temperature-dependence of the phase coherence length on the conductivity of magnetic topological insulators

TL;DR

This paper experimentally shows that the sign of quantum corrections to conductivity in magnetic topological insulators can reverse due to temperature-dependent scattering lengths, independent of Berry phase changes.

Contribution

It demonstrates that sign reversal of quantum corrections can occur without Berry phase suppression, highlighting the role of temperature-dependent scattering lengths.

Findings

Quantum correction sign reverses without Berry phase change

Inelastic scattering length decreases with temperature below Curie transition

Sign reversal linked to temperature-dependent scattering processes

Abstract

Magnetotransport constitutes a useful probe to understand the interplay between electronic band topology and magnetism in spintronics devices based on topological materials. A recent theory of Lu and Shen [Phys. Rev. Lett. 112, 146601 (2014)] on magnetically doped topological insulators predicts that quantum corrections $\Delta\kappa$ to the temperature-dependence of the conductivity can change sign during the Curie transition. This phenomenon has been attributed to a suppression of the Berry phase of the topological surface states at the Fermi level, caused by a magnetic energy gap. Here, we demonstrate experimentally that $\Delta\kappa$ can reverse its sign even when the Berry phase at the Fermi level remains unchanged, provided that the inelastic scattering length decreases with temperature below the Curie transition.