Orbital angular momentum for spintronics

A novel platform for spin manipulation utilizing the orbital angular momentum (OAM) is preparing the next innovation of spintronics. Analogous to the generation of the spins by the inverse spin Galvanic effect, we could construct a nonzero OAM at surfaces and interfaces with the structural inversion asymmetry or in centrosymmetric bulks. However, all these generation mechanisms are irrelevant to the spin–orbit coupling (SOC) strength, presenting the distinction from the spin generation mechanisms. The nonzero OAM could be utilized for highly efficient spin manipulation, supported by several recent experimental reports. These reports indicate that light metal elements are also useful for OAM-induced spin manipulation. Also, the collaborative spin manipulation by the OAM and the spin angular momentum (SAM) opens an alternative mechanism. Here we review experimental and theoretical new findings on the OAM-induced or OAM–assisted spin manipulation. All these new findings indicate that the OAM-induced spin manipulation opens the door to novel spintronics in terms of mechanism and materials.