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

Abstract

In this paper, we study the spin Nernst effect 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 spin Nernst effect is expected to occur in various Néel antiferromagnetic materials even without the Dzyaloshinskii-Moriya interaction. In particular, the nonlinear spin Nernst current in the honeycomb and diamond lattice antiferromagnets can be controlled by strain/pressure.