Electrical detection of the inverse Edelstein effect on the surface of SmB6

Abstract

We report the measurement of spin current-induced charge accumulation, the inverse Edelstein effect (IEE), on the surface of single-crystal candidate topological Kondo insulator SmB6. The robust surface conduction channel of SmB6 has been shown to exhibit a large degree of spin-momentum locking, and the spin-polarized current through an external ferromagnetic contact induces spin-dependent charge accumulation on the surface of SmB6. The dependence of the IEE signal on the bias current, an external magnetic field direction, and temperature are consistent with an anticlockwise spin texture of the SmB6 surface band in momentum space. The direction and magnitude of this effect, compared with the normal Edelstein signal, are clearly explained by the Onsager reciprocal relation. Furthermore, we estimate the spin-to-charge conversion efficiency, i.e., the IEE length, to be 4.46 nm, which is an order of magnitude larger than the efficiency found in other typical Rashba interfaces, implying that the Rashba contribution to the IEE signal may be small. Building upon existing reports on the surface charge and spin conduction nature of this material, our results provide additional evidence that the surface of SmB6 supports a spin-polarized conduction channel.