Magnon heat transport in an antiferromagnetic insulator

We theoretically investigate the magnon heat transport in an antiferromagnetic (AFM) insulator containing an atomically sharp domain wall (DW) in the presence of a magnetic field. It has been known that, while in the continuum approximation and in the absence of a magnetic field a spin wave is able to pass through a DW without reflection, a narrow DW gives rise to finite reflection coefficients which modify the magnon heat transport [1]. In this work, we investigate the effect of an external field on the magnon heat transport in the presence of a sharp domain wall. Specifically, we find that applying a magnetic field lifts the degeneracy between two AFM magnon modes of opposite polarizations. This results in different occupation numbers for the two magnon modes, which along with the finite reflection coefficients is found to have a significant impact on the magnon heat transport, offering a way to realize a tunable heat transport in an AFM DW.