Anisotropic Spin Hall Angle in Semimetal WTe 2 with a ferromagnet Fe 3 GeTe 2 Spin Source

Abstract The interplay between reduced crystal symmetry and strong spin-orbit coupling in semimetallic WTe 2 generates unique spin transport phenomena, positioning it as a focal material in condensed matter physics and spintronics. In this work, we achieve crystallographic control of the spin Hall effect (SHE) through a tailored WTe 2 /Fe 3 GeTe 2 (FGT) van der Waals heterostructure. By fabricating dual Hall bar channels along the crystallographically distinct zig-zag a -axis and armchair b -axis, we enable direct comparison of spin-to-charge conversion anisotropy under identical spin injection conditions via the FGT ferromagnetic layer. Field-dependent measurements reveal a pronounced threefold enhancement in the spin Hall angle along the a -axis compared to the b -axis, modeled through synchronized spin polarization and diffusion dynamics. Our methodology establishes an universal framework for probing symmetry-directed spin transport in quantum materials, offering a pathway toward energy-efficient spintronic devices such as high-density memory and logic operations without external magnetic fields.