Magnon equilibrium spin current in collinear antiferromagnets

Abstract

We theoretically predict that the Dzyaloshinskii-Moriya interaction can induce a magnon equilibrium spin current in collinear antiferromagnets. Such a current, being a response to the effective magnon vector potential, can be considered the magnon analog of the supercurrent in superconductors. The large amplitude of the predicted effect may compensate for the smallness of the Dzyaloshinskii-Moriya interaction, making the equilibrium spin currents experimentally observable. We suggest that an external electric field can play the role of an effective flux that magnons interact with, and we propose an experiment based on the interference of magnons in a ring geometry to verify the concept.