Molecular engineering of spintronics phenomena arising from Rashba spin-orbit interaction

In heterostructures with broken inversion symmetry, the electrons' motion is coupled to their spin through interface-driven spin-orbit coupling: Rashba spin-orbit coupling. The Rashba spin-orbit coupling enables direct conversion between spin and charge currents, promising high-performance, low-power spintronic memory and logic devices. Over the past 20 years, the control of this coupling has been the foundation of semiconductor spintronics. In contrast, the engineering of metallic Rashba spin-orbit devices remains a major challenge. Recently, we found that molecular self-assembly provides a way to engineer these devices. This article introduces the role of spin-orbit coupling in modern spintronics and presents recent experimental results on the phenomena arising from the Rashba spin-orbit coupling, including the Rashba-Edelstein effect and Rashba-Edelstein magnetoresistance. The Rashba-induced phenomena in metallic heterostructures are shown to be tuned by molecular self-assembly, which enables reversible phototuning of spin-charge conversion through light-driven molecular transformations. This finding, with the almost-infinite chemical tunability of organic monolayers, paves the way toward the molecular engineering of spin-orbit devices. (author)