Theory of Cross-correlated Electron-Magnon Transport Phenomena: Case of Magnetic Topological Insulator

TL;DR

This paper develops a theoretical framework for cross-correlated heat and electric transport phenomena involving magnons and Dirac electrons on ferromagnetic topological insulators, revealing novel thermoelectric and thermal Hall effects.

Contribution

It introduces a comprehensive theory for electron-magnon cross-correlated transport phenomena, including new effects like magnon- and electron-drag thermoelectric and thermal Hall effects in magnetic topological insulators.

Findings

Magnon- and electron-drag thermoelectric effects caused by magnon-induced electromotive force.

Thermal and thermoelectric analogs of anisotropic magnetoresistance (AMR) in these systems.

Thermal AMR as a magnonic analog of AMR in the insulating state.

Abstract

We study transport phenomena cross-correlated among the heat and electric currents of magnons and Dirac electrons on the surface of ferromagnetic topological insulators. For a perpendicular magnetization, we calculate magnon- (electron-) drag anomalous Nernst/Seebeck (anomalous Ettingshausen/Peltier) effects and magnon-/electron-drag thermal Hall effects. The magnon-drag thermoelectric effects are interpreted to be caused by magnon-induced electromotive force. When the magnetization has in-plane components, there arise thermal/thermoelectric analogs of anisotropic magnetoresistance (AMR). In the insulating state, the thermal AMR is realized as a magnonic analog of AMR.