Direct and alternating magnon spin currents across a junction interface irradiated by linearly polarized laser

TL;DR

This paper proposes a novel method to generate and control direct and alternating magnon spin currents across a junction using linearly polarized laser irradiation, with potential for experimental realization in quantum magnonics.

Contribution

It introduces an analytic model for magnon spin current generation via laser irradiation and demonstrates enhancement through ferromagnetic resonance, highlighting a new approach in magnonics.

Findings

Spin currents are enhanced by ferromagnetic resonance.

The period of the ac spin current is half of the laser magnetic field period.

Estimated spin current magnitude is within experimental reach.

Abstract

The developments in the field of quantum optics raise expectations that laser-matter coupling is a promising building block for magnonics. Here, we propose a method for the generation of direct and alternating spin currents of magnons across the junction interface irradiated by linearly polarized laser. In a junction of ferromagnetic insulators with a large electronic gap, the spin angular momentum is exchanged during the tunneling process of magnons across the junction interface. The advanced technology in the field of plasmonics and metamaterials realizes that spins irradiated by the laser field interact only with the magnetic component of the laser through the Zeeman coupling. Using an analytic perturbation theory, we provide a general formula for magnon transport induced by the inversion symmetry breaking across the junction interface. Then, we show that those spin currents are enhanced by the ferromagnetic resonance, and the period of the ac spin current is one-half of that of the laser magnetic field. Finally, we estimate the magnitude of the spin current, and find that it will be within experimental reach.