Antiferromagnetic Magnons - A tale of two spins
Ran Cheng (University of California, Riverside)

Magnons, the quanta of spin‐wave excitations, can transport spin angular momenta over long distances without incurring Joule heating. They are promising alternatives to electrons in building next‐generation nanotechnology. To fully function as electrons, however, magnons should bear an intrinsic degree of freedom similar to the electron spin. In antiferromagnets, spin‐up and spin‐down magnons coexist and form a unique degree of freedom capable of encoding information, which can be controlled through the Dzyaloshinskii-Moriya interaction, temperature gradient, etc. Guided by the resemblance between antiferromagnetic magnons and electrons with spin being an active variable, we propose a series of physical phenomena where magnons can function as electrons in transporting and transferring spin angular momenta, including magnon-induced interlayer coupling, spin Nernst and spin Edelstein effects, and magnonic spin torques in an insulating spin valve with antiferromagnetic spacer. These phenomena introduced a vibrant playground for new fundamental physics and opened the exciting possibility of utilizing magnons as primary information carriers in electronic devices.