Spin current generation via magnetic skyrmion, bimeron, and meron crystals

TL;DR

This paper explores how various two-dimensional topological spin textures, including skyrmion, bimeron, and meron crystals, can generate spin currents with different polarization directions, offering new insights for spintronics device design.

Contribution

It demonstrates that topological spin textures can generate spin currents without net magnetization, especially highlighting the effects of spin--orbit coupling and symmetry on spin transport.

Findings

Skyrmion and bimeron crystals generate spin currents polarized along their magnetization directions.

Meron crystals produce out-of-plane spin currents despite zero net magnetization.

Spin--orbit coupling enhances spin current generation in bimeron and meron crystals.

Abstract

Spin current offers a promising route toward energy-efficient and high-speed information processing. Developing efficient methods for their generation remains a central challenge in spintronics. Here, we investigate spin current generation via two-dimensional topological spin textures: a skyrmion crystal (SkX) with out-of-plane magnetization, a bimeron crystal (BmX) with in-plane magnetization, and a meron crystal (MX) with zero net magnetization. We show that these distinct spin textures generate spin currents with characteristic spin polarization directions. In the absence of spin--orbit coupling, the SkX and BmX generate spin currents polarized along their magnetization directions, whereas the MX yields no spin current. Upon introducing spin--orbit coupling, while the behavior of the SkX does not qualitatively change, the BmX generates nonzero spin currents in multiple polarization directions. Notably, the MX, despite its zero net magnetization, exhibits a pronounced spin current with out-of-plane spin polarization, driven by an enhanced spin Berry curvature associated with characteristic band degeneracy. We further demonstrate that the electronic and spin transport properties of each texture are governed by their magnetic symmetries. Our results highlight the topological spin textures as efficient sources of spin current even without net magnetization, expanding the design for spintronics devices based on topological magnetic metals.