Magnetization Dynamics
Our group explores how charge currents generate spin-orbit torques (SOTs) that drive magnetization dynamics in van der Waals magnets. Using fully-relativistic first‑principles calculations with symmetry‑adapted Wannier interpolation and Kubo–Bastin response theory, we map the angular dependence of SOTs in Fe₃GeTe₂ (FGT), Fe₃GaTe₂ (FGaT), and WTe₂ stacks. We find that interband “hot spots” at SOC‑mixed band anti-crossings dominate the even SOT near in‑plane magnetization, while the odd SOT is largely Fermi‑surface controlled, directly linking the band structure to current‑induced torques that govern magnetization dynamics.
Material design offers powerful control knobs: Substituting Ge by Ga effectively hole‑dopes FGT and reshapes the Berry‑curvature distributions, changing the sign and magnitude of a key SOT component across realistic disorder levels. In WTe₂/FGT, reduced crystal symmetry and interfacial Te–Te hybridization amplify damping‑like torques and introduce an out‑of‑plane spin polarization, enabling field‑free, deterministic switching. Atom‑ and layer‑resolved analyses further reveal large “hidden” (canceling) torques with a small uniform remainder, the piece that actually switches the magnet, offering practical design rules to maximize SOT efficiency.
