Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 78: Focus Session: Spinorbitronics - From Efficient Charge/Spin Conversion Based on Spin-Orbit Coupling to Chiral Magnetic Skyrmions I (joint session MA/TT)

TT 78.1: Hauptvortrag

Donnerstag, 15. März 2018, 09:30–10:00, H 1012

Understanding Spin-Charge Conversion in Topological Insulators — •Aurelien Manchon — King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division (PSE), Thuwal 23955-6900, Saudi Arabia

The interface between TI and 3d transition metal ferromagnets (3d-TM) represents a powerful platform for the realization of spin-charge conversion processes such as, but not limited to, spin pumping and spin-orbit torques. Uncovering the impact of 3d-TM overlayers on the surface states of TI and evaluating the resulting interfacial spin-momentum locking will undoubtedly open promising avenues for the efficient control of spin and charge currents mediated by spin-orbit coupling.

After a short review of the experimental results available, I will first discuss the spin-charge conversion processes expected from an ideal model. I will show that the very symmetry of the spin-orbit torques expected from topological surface states is quite different from the one observed experimentally. In a second part, based on recent density functional theory calculations, I will discuss the nature of interfacial orbital hybridization in 3d-TM adsorbed on Bi2Se3. Finally, based on these considerations I will present a minimal tight-binding model that allows us to inspect the transition between surface-dominated and bulk-dominated spin-orbit torque in 3d-TM/Bi2Se3 bilayers. This last model demonstrates that spin Hall effect arising from the bulk states of the topological insulator are unlikely to contribute to the last torque observed in experiments.