  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.
