A perspective on magnon spin Nernst effect in antiferromagnets

Magnon excitations in antiferromagnetic materials and their physical implications have helped to facilitate the emergence of device concepts not presently available in ferromagnets. A unique characteristic of antiferromagnetic magnons is the coexistence of opposite spin polarization, which mimics the electron spin in a variety of transport phenomena. Among them, the most prominent spin-contrasting phenomenon is the magnon spin Nernst effect (SNE), which refers to the generation of a transverse pure magnon spin current through a longitudinal temperature gradient. We introduce selected recent progress in the study of magnon SNE in collinear antiferromagnets with focus on its underlying physical mechanism entailing profound topological features of magnon band structures. By reviewing how the magnon SNE has inspired and enriched the exploration of topological magnons, we offer our perspective on this emerging frontier that holds potential in future spintronic nano-technology.