Unraveling the dynamics of magnetization in topological insulator-ferromagnet heterostructures via spin-orbit torque

Abstract: Spin-orbit coupling stands as a pivotal determinant in the realm of condensed matter physics. In recent, its profound influence on spin dynamics opens up a captivating arena with promising applications. Notably, the topological insulator-ferromagnet heterostructure has been recognized for inducing spin dynamics through applied current, driven by spin-orbit torque. Building upon recent observations revealing spin flip signals within this heterostructure, our study elucidates the conditions governing spin flips by studying the magnetization dynamics. We establish that the interplay between spin-anisotropy and spin-orbit torque plays a crucial role in shaping the physics of magnetization dynamics within the heterostructure. Furthermore, we categorize various modes of magnetization dynamics, constructing a comprehensive phase diagram across distinct energy scales, damping constants, and applied frequencies. This research not only offers insights into controlling spin direction but also charts a new pathway to the practical application of spin-orbit coupled systems.