Probing orbital currents through inverse orbital Hall and Rashba effects

Abstract Orbital angular momentum of electrons has recently emerged as a new degree of freedom for information transport, extending the principles of spintronics into the broader field of orbitronics. In this framework, orbital currents can exist even in the absence of strong spin-orbit coupling, enabling charge manipulation in light materials and semiconductors. Here, we experimentally probe orbital-to-charge conversion through the inverse orbital Hall (IOHE) and inverse orbital Rashba (IORE) effects. Using spin pumping and spin Seebeck excitation in YIG/Pt/NM heterostructures, where NM is a metal or semiconductor, we demonstrate efficient orbital current generation and detection. We find that the orbital contribution dominates over spin effects, even in weak-SOC systems. Strong enhancement of conversion signals is observed at naturally oxidized Cu interfaces, and opposite IOHE polarities are found in Ti and Ge. Our results establish direct experimental evidence of orbital transport, providing key insights for the development of next-generation orbitronic devices.