Rectification of the spin Seebeck current in noncollinear antiferromagnets

TL;DR

This paper investigates how the spin Seebeck effect behaves in noncollinear antiferromagnets, revealing that despite magnon flow, the net spin current cancels out due to opposite magnetic moment orientations.

Contribution

It provides a theoretical analysis of the magnonic spin Seebeck effect in noncollinear antiferromagnets, highlighting the cancellation of net spin current despite magnon flow.

Findings

Magnon flow occurs from hot to cold edge under thermal bias.

Opposite magnetic moment orientations lead to zero net spin current.

Magnonic spin Seebeck current is present without net spin transfer.

Abstract

In the absence of an external magnetic field and a spin-polarized charge current, an antiferromagnetic system supports two degenerate magnon modes. An applied thermal bias activates the magnetic dynamics, leading to a magnon flow from the hot to the cold edge (magnonic spin Seebeck current). Both degenerate bands contribute to the magnon current but the orientations of the magnetic moments underlying the magnons are opposite in different bands. Therefore, while the magnon current is nonzero, the net spin current is zero.