Topology for Magnetization Control in Complex Magnets

The topological properties of magnets as encoded in the Berry phase have revolutionized our understanding of elementary transport effects. The discovery that the non-trivial geometry of reciprocal space relates to orbital properties of electrons allows us to predict from theoretical arguments pronounced orbital magnetism in various situations ranging from Rashba systems to Chern insulators [1-3]. We demonstrate that the combination of complex geometry in real and momentum spaces manifests in the emergence of topological orbital magnetism in non-collinear magnets, which opens new vistas in large current-induced orbital response and magnetization manipulation in antiferromagnets [1,2]. Finally, we predict that in insulating systems with complex topologies the magnitude of magneto-electric phenomena in terms of spin-orbit torques and Dzyaloshinskii-Moriya interaction can exceed significantly that of conventional metallic magnets, which lays out promising perspectives for the dissipationless magnetization control in nanomagnets [4].

[1] Hanke et al., Phys. Rev. B 94, 121114(R) (2016).
[2] Hanke et al., Sci. Rep. 7, 41078 (2017).
[3] Go et al., Sci. Rep. 7, 46742 (2017).
[4] Hanke et al., arXiv:1701.08050 (Nat. Commun. in press).