Orbitronics: Mechanism of Orbital Current Generation and Dynamics

Abstract

The orbital degree of freedom is often considered to be quenched in solids due to the potential of the crystal field. In contrast to such expectation, we showed recently that the orbital current can be electrically generated despite orbital quenching in equilibrium, leading to a phenomenon called the orbital Hall effect. In this article, we provide a pedagogical introduction to the concept of an orbital current in solids and the mechanism underlying the orbital Hall effect. We also discuss the relation between the orbital Hall effect and the spin Hall effect, as well as a way to utilize the orbital current in spin-orbitronic devices.