Nonlinear magnon spin Nernst effect in antiferromagnets and strain-tunable pure spin current

TL;DR

This paper investigates the nonlinear magnon spin Nernst effect in antiferromagnets, deriving a new formula that links it to Berry curvature dipoles, and shows it can be tuned by strain or pressure.

Contribution

It introduces a theoretical framework for the nonlinear magnon spin Nernst effect and demonstrates its control via strain in antiferromagnetic materials.

Findings

Nonlinear magnon SNE described by extended Berry curvature dipole.

Occurrence in Nél antiferromagnets without Dzyaloshinskii-Moriya interaction.

Strain/pressure tuning of the nonlinear spin Nernst current.

Abstract

In this Letter, we study the spin Nernst effect (SNE) of magnons in the nonlinear response regime. We derive the formula for the nonlinear magnon spin Nernst current by solving the Boltzmann equation and find out that it is described by an extended Berry curvature dipole of magnons. The nonlinear magnon SNE is expected to occur in various N\'eel antiferromagnets without Dzyaloshinskii-Moriya interaction. In particular, the nonlinear spin Nernst current in the honeycomb and diamond lattice antiferromagnets can be controlled by strain/pressure.