Disorder effect on magneto-transport on the surface of a topological insulator

TL;DR

This paper investigates how disorder affects magneto-transport on the surface of topological insulators with ferromagnetic junctions, revealing different behaviors for in-plane and out-of-plane magnetizations and showing robustness of in-plane magnetoconductance.

Contribution

It provides a detailed analysis of disorder effects on magneto-transport in topological insulator surfaces with ferromagnetic coupling, highlighting the distinct mechanisms for different magnetization orientations.

Findings

In-plane magnetoconductance is robust against disorder.

Out-of-plane magnetoconductance is more sensitive to disorder.

Different mechanisms govern magneto-transport for in-plane and out-of-plane magnetizations.

Abstract

We study the magneto-transport properties on the disordered surface of a topological insulator attached with a ferromagnet/ferromagnet junction. Since, in the surface Dirac Hamiltonian, out-of-plane magnetization induces a mass gap, while in-plane magnetization has a role of the effective vector potential, the mechanism of magneto-transport is different between these two cases. The former is similar to the conventional one in ferromagnetic metals, while the latter is due to the shift of Fermi circles in momentum space. Our numerical calculations show that the magnetoconductance in in-plane configuration is robust against disorder compared to that in out-of-plane configuration.