Proximity-induced nonlinear magnetoresistances on topological insulators

TL;DR

This paper investigates how interfacial disorder and spin-orbit scattering induce nonlinear magnetoresistances in topological insulator bilayers, revealing strong Fermi energy dependence and potential for probing magnetic interactions.

Contribution

It introduces a quadratic-response Kubo approach to predict nonlinear magnetotransport effects driven by interfacial phenomena in topological insulator/magnetic insulator bilayers.

Findings

Nonlinear magnetoresistance and Hall effects are predicted.

Transport coefficients are greatly amplified near the exchange energy.

Dependencies on magnetization orientation deviate from sinusoidal behavior.

Abstract

We employ quadratic-response Kubo formulas to investigate the nonlinear magnetotransport in bilayers composed of a topological insulator and a magnetic insulator, and predict both unidirectional magnetoresistance and nonlinear planar Hall effects driven by interfacial disorder and spin-orbit scattering. These effects exhibit strong dependencies on the Fermi energy relative to the strength of the exchange interaction between the spins of Dirac electrons and the interfacial magnetization. In particular, as the Fermi energy becomes comparable to the exchange energy, the nonlinear magnetotransport coefficients can be greatly amplified and their dependencies on the magnetization orientation deviate significantly from conventional sinusoidal behavior. These findings may not only deepen our understanding of the origin of nonlinear magnetotransport in magnetic topological systems but also open new pathways to probe the Fermi and exchange energies via transport measurements.