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MA: Fachverband Magnetismus

MA 48: Spin Dynamics and Transport: Spin Excitations and Spin Torque Phenomena

MA 48.8: Vortrag

Donnerstag, 23. März 2017, 11:30–11:45, HSZ 101

Spin-orbit torques in Chern insulators — •Jan-Philipp Hanke, Frank Freimuth, Stefan Blügel, and Yuriy Mokrousov — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Spin-orbit torques (SOTs) arise as a result of an applied electric field in systems that combine broken spatial inversion symmetry and spin-orbit coupling. They allow for an efficient magnetization control in single ferromagnetic layers [1] mediated by the current-induced exchange of angular momentum between crystal lattice and magnetization. While previous works focused on SOTs in topologically trivial materials such as magnetic bilayers, the nature and magnitude of this phenomenon in insulators with globally nontrivial topology in reciprocal space was hardly addressed. Here, employing density functional theory and model calculations, we make contact with the field of Chern and topological insulators by investigating the SOT and Dzyaloshinskii-Moriya interaction (DMI) in a topologically complex system of magnetically-doped graphene. Both phenomena reveal unique fingerprints of the underlying topology, and we evaluate their interplay with the magnetization direction using higher-dimensional Wannier functions [2]. Remarkably, despite the absence of a longitudinal current, we predict that the magnitude of SOT and DMI in this family of Chern insulators is comparable to that observed in conventional magnetic metallic materials, which opens new vistas for dissipationless electric magnetization control.

[1] I. M. Miron et al., Nature 476, 189 (2011).

[2] J.-P. Hanke et al., Phys. Rev. B 91, 184413 (2015).