Field-free highly efficient spin-orbit torque switching in Fe3GaTe2 at room temperature enabled by a unique distorted crystal symmetry of WTe2

Spin-orbit torque (SOT) is a highly viable mechanism for achieving low-energy and high-speed switching in spintronic devices. Two-dimensional (2D) van der Waals (vdW) materials and their heterostructures have proven their scalability and energy effectiveness for device operation. Here, we demonstrate that SOT can be robustly realized in a heterostructure composed of the 2D-vdW ferromagnetic material (FM) Fe₃GaTe₂ (FGaT) and the 2D-vdW topological semimetal WTe₂ at room temperature. The anisotropic Fermi surface originating from the uniquely reduced crystal symmetry of WTe₂ enables field-free deterministic SOT switching. We report an unprecedentedly low threshold switching current density of 6.5 × 10⁹ A m⁻² at zero field and a spin Hall angle (${\theta }_{SH})$ of 8.5. These results demonstrate a nearly 100-fold improvement in device performance over all previously reported 3D heavy metal (HM)/FM systems, supported by a second harmonic-modulated nonlinear signal measurement implemented to ensure SOT analysis and reliability. The spin Hall conductivity $\left({\sigma }_{SH}\right)$ and the switching power density $\left(P_{sw}\right)$ reported are about 1.3 × 10⁶ S m⁻¹ and 0.33 × 10¹⁵ W m⁻³, respectively, supporting the efficient device performance at low power consumption. Our result highlights that Fe₃GaTe₂, coupled with the strong spin–orbit coupling and low crystal symmetry of WTe₂, in the form of 2D-vdW heterostructure (WTe₂/Fe₃GaTe₂), offers a promising platform for generating substantial torque on magnetization at room temperature. This leads to more efficient and easier switching, paving the way for developing next-generation, highly advanced, room-temperature spin-electronic devices.