Hidden interplay of current-induced spin and orbital torques in bulk Fe3GeTe2

Abstract

Low crystal symmetry of magnetic van der Waals materials naturally promotes spin-orbital complexity unachievable in common magnetic materials used for spin-orbit torque switching. Here, using first-principles methods, we demonstrate that an interplay of spin and orbital degrees of freedom has a profound impact on spin-orbit torques in the prototypical van der Waals ferromagnet Fe3GeTe2. While we show that bulk Fe3GeTe2 hosts strong “hidden” current-induced torques harvested by each of its layers, we uncover that their origin alternates between the conventional spin flux torque and the so-called orbital torque as the magnetization direction is varied. A drastic difference in the behavior of the two types of torques results in a nontrivial evolution of switching properties with doping. Our findings promote the design of nonequilibrium orbital properties as the guiding mechanism for crafting the properties of spin-orbit torques in layered van der Waals materials.