Abstract
Topological insulators (TIs) have emerged as some of the most efficient spin-to-charge convertors because of their correlated spin-momentum locking at helical Dirac surface states. While endeavors have been made to pursue large charge-to-spin conversions in novel TI materials using spin-torque-transfer geometries, the reciprocal process spin-to-charge conversion, characterized by the inverse Edelstein effect length (lambda(IEE)) in the prototypical TI material (Bi2Se3), remains moderate. Here, we demonstrate that, by incorporating a second spin-splitting band, namely, a Rashba interface formed by inserting a bismuth interlayer between the ferromagnet and the Bi2Se3 (i.e., ferromagnet/Bi/Bi2Se3 heterostructure), lambda(IEE) shows a pronounced increase (up to 280 pm) compared with that in pure TIs. We found that lambda(IEE) alters as a function of bismuth interlayer thickness, suggesting a new degree of freedom to manipulate lambda(IEE) by engineering the interplay of Rashba and Dirac surface states. Our finding launches a new route for designing TI- and Rashba-type quantum materials for next-generation spintronic applications.