Magnetization in Nonmagnetic Heterobilayers Induced by Linearly Polarized Light.

Abstract

Light-spin interactions attract a great deal of interest both for their fundamental physics and for their potential applications. Despite substantial theoretical and experimental efforts, inducing magnetization in intrinsically nonmagnetic systems using linearly polarized light constitutes a critically underdeveloped research frontier. Here, we propose a novel mechanism for generating light-induced magnetization in nonmagnetic van der Waals heterobilayers under linearly polarized light. Our mechanism emerges from the synergistic interplay between light-driven nonequilibrium carrier dynamics and electronic instabilities associated with van Hove singularities. Specifically, ultrafast linearly polarized light creates nonequilibrium carriers near the van Hove singularities, promoting spin-flip processes mediated by spin-orbit coupling during carrier relaxation, which subsequently triggers remarkable spin polarization. Using a combination of first-principles calculations and real-time time-dependent density functional theory, we further confirm this paradigm in the InS/GaSe heterobilayer. Our findings open a new direction for research on light-spin interactions.