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Interfacial spin-orbit torques (SOTs) enable manipulation of the magnetization through an in-plane charge current, which has drawn increasing attention for spintronic applications. In the search for material systems that can provide efficient SOTs, much work has been focused on polycrystalline ferromagnetic metal/non-magnetic metal bilayers [1-3]. Here the current flows in the non-magnetic layers and induces a torque at the interfaces via the spin Hall effect of the non-magnetic layer [1], the Rashba effect at the interface [2] or spin-momentum locking when a topological insulator is involved [3]. In this presentation, we report the observation of robust SOT occuring in a well characterized single crystalline Fe/insulating GaAs (001) interface at room temperature where the SOT is caused by the lack of space inversion symmetry at the interface. We find that the magnitude of the interfacial SOT per unit charge current density is comparable in strength with that in ferromagnetic metal/non-magnetic metal systems. This large magnitude also allows for the observation of spin-to-charge current conversion at the interface, which is known as spin-galvanic effect [4]. The results suggest that single crystalline Fe/GaAs interfaces may enable efficient magnetization manipulation through purely electric means [5].
References
[1] L. Liu, et al., Science 336, 555 (2012).
[2] I. M. Miron, et al., Nature 476, 189 (2011).
[3] A. R. Mellnik, et al., Nature 511, 449 (2014).
[4] S. D. Ganichev, et al., Nature 417, 153 (2002).
[5] L. Chen, et al., Nature Commun. 7, 13802 (2016).
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