Zero-bias Giant Rashba Spin-Orbit Coupling Controlled by Carrier Modulation Layer*

The Landauer’s principle dictates a fundamental physical limitation for the switching energy. A primary solution in breaking this limitation is to utilize the spin-orbit coupling (SOC) effect at broken inversion symmetry, as it allows easy manipulation of spin currents. However, this SOC effect is often quite weak, especially in the absence of external voltage biases. We report a four-fold SOC enhancement at zero bias voltage and pronounced SOC evolution in correlated LaAlO₃-SrTiO₃ heterostructures buffered by a carrier modulating LaFeO₃ layer. We use an entirely new model to provide evidence of generating Rashba SOC. Correlating the magnetotransport data with first-principles calculations and high-resolution electron microscopy, we reveal that its origin lies in the asymmetric hybridization of the interfacial wavefunctions. Our results open hitherto unexplored avenues of generating and controlling Rashba coupling to design next-generation two-dimensional electron system based spin-orbitronic devices.