Magnetization Dynamics of a Ferromagnet Attached to the edge State of a 2DTopological Insulator: A Time Dependent nonequilibrium Green's Function Approach

Nowadays huge effort is focused on the investigation of spin orbit torque (SOT) and theresulting magnetization dynamics in order to find next generation promising spintronicdevices based on both the current-induced magnetization switching (CIMS) and also thecurrent-induced domain wall motion (CIDWM) [1]. A deep understanding and proper controlof current-induced magnetization dynamics in 2D Topological Insulator (2DTIs), (typicallyknown as systems that show Quantum Spin Hall Effect), had received considerable attentiontowards large spin orbit coupling (SOC) induced spin torque in such systems. Meng et al.,had shown that current through a helical edge state of QSH insulator, considering themagnetic anisotropy energy, can be entirely transmitted via magnetically gapped region dueto combination of the spin transfer torque (STT) and spin pumping phenomena [2].