We unambiguously identify, in experiment and theory, an overlooked holographic interference pattern in strong-field ionization, dubbed "the spiral," stemming from two trajectories where the potential and laser field are equally critical. Because of the strong interaction with the core of the two trajectories, the spiral could be employed as an optimal tool for probing the target after ionization and for revealing obfuscated phases in the bound states. We find that the spiral is responsible for interference carpets, formerly ascribed to direct trajectories, and that the carpet-interference condition is derived from the field symmetry. This case of mistaken identity may have prevented the spiral from being used as a holographic tool.

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 "spinto-charge" conversion, characterized by the inverse Edelstein effect length (λ IEE ) in the prototypical TI material (Bi 2 Se 3 ), 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 Bi 2 Se 3 (i.e., ferromagnet/Bi/Bi 2 Se 3 heterostructure), λ IEE shows a pronounced increase (up to 280 pm) compared with that in pure TIs. We found that λ IEE alters as a function of bismuth interlayer thickness, suggesting a new degree of freedom to manipulate λ 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.

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