Theory for Magneto-Optical Detection of the Interfacial Orbital Rashba-Edelstein Effect

The preprint operates within the established paradigm of spintronics and the emerging, closely related paradigm of orbitronics in condensed matter physics. This framework seeks to understand and utilize the spin and orbital angular momentum of electrons for new technologies. The research uses standard, powerful theoretical tools of the paradigm—namely first-principles density functional theory and linear-response theory—to investigate current-induced phenomena in magnetic heterostructures like Co/Pt bilayers, which are canonical systems within this research program.

This work is classified as Normal Science because it engages in a form of "puzzle-solving" that refines and articulates the existing paradigm. The authors address a specific puzzle: the physical origin of a recently observed magneto-optical signal. By developing a detailed theoretical model, they propose that the signal originates from the Orbital Rashba-Edelstein Effect (OREE), offering a new interpretation that challenges the previous attribution to a spin-based effect. This does not create a crisis but rather deepens the paradigm's explanatory power by providing a more precise, quantitative theoretical foundation for detecting and understanding orbital effects.