Spintronics meets orbitronics: Emergence of orbital angular momentum in solids

One of the ultimate goals of spintronics is to realize an efficient electrical manipulation of spin for high-speed and low-power nanodevices. A core ingredient for achieving this goal is the relativistic interaction between the electron’s orbital motion and spin, but the properties of the orbital angular momentum itself have remained largely unexplored. However, recent theories and experiments have uncovered that electrons may acquire nonvanishing orbital angular momentum when an external electric field is applied, even without the spin–orbit coupling. These findings have spurred the emergence of a burgeoning field known as orbitronics, which harnesses the orbital angular momentum to manipulate magnetic devices. In this Review, we provide an overview of the recent developments in orbitronics and discuss their implications for spintronics. We then outline future avenues of research at the intersection of spintronics and orbitronics.