Spin Seebeck effect in the classical easy-axis antiferromagnetic chain

TL;DR

This study uses molecular dynamics simulations to explore the spin Seebeck effect in a classical easy-axis antiferromagnetic chain, revealing phase-dependent behaviors and a divergence of spin current at the spin-flop transition, providing insights relevant to experimental observations.

Contribution

It demonstrates the phase-dependent behavior of the spin Seebeck effect and identifies a divergence of spin current at the spin-flop transition through simulations and analysis.

Findings

Distinct behavior in different magnetic phases

Divergence of spin current at the spin-flop transition

Sign change of spin current with temperature gradient

Abstract

By molecular dymanics simulations we study the spin Seebeck effect as a function of magnetic field in the prototype classical easy-axis antiferromagnetic chain, in the far-out of equilibrium as well as linear response regime. We find distinct behavior in the low field antiferromagnetic, middle field canted and high field ferromagnetic phase. In particular, in the open boundary system at low temperatures, we observe a divergence of the spin current in the spin-flop transition between the antiferromagnetic and canted phase, accompanied by a change of sign in the generated spin current by the temperture gradient. These results are corroborated by a simple spin-wave phenomenological analysis and simulations in the linear response regime. They shed light on the spin current sign change observed in experiments in bulk antiferromagnetic materials.