Electrical detection of the inverse Edelstein effect on the surface of SmB$_6$

TL;DR

This study demonstrates the electrical detection of the inverse Edelstein effect on SmB6's surface, revealing significant spin-momentum locking and high spin-to-charge conversion efficiency, supporting its potential in spintronic applications.

Contribution

First measurement of the inverse Edelstein effect on SmB6 surface, showing high efficiency and confirming spin-polarized surface conduction in this topological Kondo insulator.

Findings

Inverse Edelstein effect observed on SmB6 surface

Spin-to-charge conversion efficiency estimated at 4.46 nm

Surface conduction exhibits spin-momentum locking

Abstract

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