Intrinsic Second-Order magnon Thermal Hall Effect

TL;DR

This paper investigates the intrinsic second-order magnon thermal Hall effect, deriving its conductivity using two methods and demonstrating control via material parameters in a ferromagnetic lattice.

Contribution

It introduces a theoretical framework for the intrinsic second-order magnon thermal Hall conductivity based on thermal scalar and vector potentials.

Findings

The second-order magnon thermal Hall conductivity is linked to thermal Berry-connection polarizability.

The conductivity can be tuned by Dzyaloshinskii-Moriya interaction strength.

Strain application allows control over the second-order thermal Hall effect.

Abstract

In this paper, we study the intrinsic contribution of nonlinear magnon thermal Hall Effect. We derive the intrinsic second order thermal Hall conductivity of magnon by the thermal scalar potential (TSP) method and the thermal vector potential (TVP) method. We find that the intrinsic second order magnon thermal Hall conductivity is related to the thermal Berry-connection polarizability (TBCP). We apply our theory to the monolayer ferromagnetic Hexagonal lattice, and we find that the second order magnon thermal Hall conductivity can be controlled by changing Dzyaloshinskii-Moriya strength and applying strain.