Orbital Magnetization Induced by Nonlinear Optical Response in Semiconductors

In recent years, there has been an emerging interest in the field of orbitronics, where the electron orbital angular momentum is utilized as an information carrier or as a means to manipulate spin angular momentum in spintronics applications. In this work, we demonstrate, using first-principles calculations within the GW-BSE approach, that a second-order optical response in two-dimensional (2D) materials can lead to the generation of a giant out-of-plane orbital moment. This phenomenon is known as the nonlinear optical orbital Edelstein effect, and the strong electron-hole interactions in 2D materials enhance the response. Our predictions show that the sign of the induced orbital moment can be controlled by the incident photon energy, leading to potential applications in using the induced moments to switch the direction of magnetization in non-volatile magnetic memory devices. This work paves the way for all-optical control and generation of angular momentum in nanoscale materials.