Rigorous theoretical description of effective skyrmion mass near angular momentum compensation

Develop a rigorous theoretical description of the effective mass of ferrimagnetic Néel skyrmions in two-sublattice systems near the angular momentum compensation temperature, characterizing its temperature dependence and clarifying how mass reduction contributes to accelerated magnetization dynamics, the disappearance of the skyrmion Hall effect, and the observed velocity maximum under spin-orbit torque.

Background

The authors observe that skyrmion velocities peak and the skyrmion Hall angle vanishes near the angular momentum compensation temperature, consistent with prior theory and experiments. They discuss qualitative explanations involving changes in collective precession modes and suggest a possible link to reduced effective skyrmion mass.

Despite these insights, the paper notes the absence of a rigorous theoretical description for the effective skyrmion mass and its role near compensation. Establishing such a framework would help unify observations of enhanced dynamics and clarify the mechanisms underlying velocity maxima in ferrimagnetic skyrmion motion.