Spin torque and Nernst effects in Dzyaloshinskii-Moriya ferromagnets

TL;DR

This paper predicts that temperature gradients can generate magnon-mediated torques and spin currents in Dzyaloshinskii-Moriya ferromagnets, revealing new spintronic effects driven by magnon Berry curvature.

Contribution

It introduces a microscopic linear response theory for magnon-mediated torques and spin currents, highlighting interband and intraband contributions in systems with Dzyaloshinskii-Moriya interactions.

Findings

Magnon-mediated spin Nernst effect demonstrated in kagome lattice ferromagnet.

Intrinsic torque induced by temperature gradients in systems with non-trivial magnon Berry curvature.

Theoretical framework distinguishes interband and intraband contributions to spin responses.

Abstract

We predict that a temperature gradient can induce a magnon-mediated intrinsic torque and a transverse spin current in systems with non-trivial magnon Berry curvature. With the help of a microscopic linear response theory of nonequilibrium magnon-mediated torques and spin currents we identify the interband and intraband components that manifest in ferromagnets with Dzyaloshinskii-Moriya interactions and magnetic textures. To illustrate and assess the importance of such effects, we apply our theory to the magnon-mediated spin Nernst and torque responses in a kagome lattice ferromagnet.