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Highly efficient and tunable spin-to-charge conversion through Rashba coupling at oxide interfaces

The spin–orbit interaction couples the electrons’ motion to their spin. As a result, a charge current running through a material with strong spin–orbit coupling generates a transverse spin current (spin Hall effect, SHE) and vice versa (inverse spin Hall effect, ISHE). The emergence of SHE and ISHE...

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Bibliographic Details
Published in:Nature materials 2016-12, Vol.15 (12), p.1261-1266
Main Authors: Lesne, E., Fu, Yu, Oyarzun, S., Rojas-Sánchez, J. C., Vaz, D. C., Naganuma, H., Sicoli, G., Attané, J.-P., Jamet, M., Jacquet, E., George, J.-M., Barthélémy, A., Jaffrès, H., Fert, A., Bibes, M., Vila, L.
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Language:English
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Summary:The spin–orbit interaction couples the electrons’ motion to their spin. As a result, a charge current running through a material with strong spin–orbit coupling generates a transverse spin current (spin Hall effect, SHE) and vice versa (inverse spin Hall effect, ISHE). The emergence of SHE and ISHE as charge-to-spin interconversion mechanisms offers a variety of novel spintronic functionalities and devices, some of which do not require any ferromagnetic material. However, the interconversion efficiency of SHE and ISHE (spin Hall angle) is a bulk property that rarely exceeds ten percent, and does not take advantage of interfacial and low-dimensional effects otherwise ubiquitous in spintronic hetero- and mesostructures. Here, we make use of an interface-driven spin–orbit coupling mechanism—the Rashba effect—in the oxide two-dimensional electron system (2DES) LaAlO 3 /SrTiO 3 to achieve spin-to-charge conversion with unprecedented efficiency. Through spin pumping, we inject a spin current from a NiFe film into the oxide 2DES and detect the resulting charge current, which can be strongly modulated by a gate voltage. We discuss the amplitude of the effect and its gate dependence on the basis of the electronic structure of the 2DES and highlight the importance of a long scattering time to achieve efficient spin-to-charge interconversion. The Rashba effect at the LaAlO 3 /SrTiO 3 interface is shown to enable large and gate-tunable spin-to-charge conversion through the inverse Rashba–Edelstein effect.The spin current is injected, through spin pumping, from a NiFe film.
ISSN:1476-1122
1476-4660
DOI:10.1038/nmat4726