N\'eel- and Bloch-Type Magnetic Vortices in Rashba Metals

TL;DR

This paper theoretically investigates noncoplanar spin textures in Rashba magnetic conductors, revealing the stabilization of N"eel- and Bloch-type vortex crystals and their transformation into skyrmion-like structures under magnetic fields.

Contribution

It introduces a new effective spin model derived from the Rashba Kondo lattice, demonstrating the emergence of vortex crystals without magnetic fields and their evolution into skyrmion-like states.

Findings

N"eel-type vortex crystal stabilized without magnetic field

Bloch-type vortex crystal realized in Rashba systems

Magnetic field induces skyrmion-like vortex structures

Abstract

We theoretically study noncoplanar spin textures in polar magnetic conductors. Starting from the Kondo lattice model with the Rashba spin-orbit coupling, we derive an effective spin model with generalized Ruderman-Kittel-Kasuya-Yosida interactions including the anisotropic and antisymmetric exchange interactions. By performing simulated annealing for the effective model, we find that a vortex crystal of N\'eel type is stabilized even in the absence of a magnetic field. Moreover, we demonstrate that a Bloch-type vortex crystal, which is usually associated with the Dresselhaus spin-orbit coupling, can also be realized in our Rashba-based model. A magnetic field turns the vortex crystals into N\'eel- and Bloch-type skyrmion-like crystals. Our results underscore that the interplay between the spin-orbit coupling and itinerant magnetism brings fertile possibilities of noncoplanar magnetic orderings.