Field‐Free Perpendicular Magnetization Switching Through Topological Surface State in Type‐II Dirac Semimetal Pt3Sn

Spin-orbit torque (SOT) induced by current is a promising approach for electrical manipulation of magnetization in advancing next-generation memory and logic technologies. Conventional SOT-driven perpendicular magnetization switching typically requires an external magnetic field for symmetry breaking, limiting practical applications. Recent research has focused on achieving field-free switching through out-of-plane SOT, with the key challenge being the exploration of new spin source materials that can generate z-polarized spins with high charge-to-spin conversion efficiency, structural simplicity, and scalability for large-scale production. This study demonstrates field-free perpendicular switching using an ultrathin type-II Dirac semimetal Pt3Sn layer with a topological surface state. Density functional theory calculations reveal that the unconventional SOT originates from a spin texture with C3v symmetry, leading to significant z-polarized spin accumulation in the Pt3Sn (111) surface, enabling the deterministic switching of perpendicular magnetization. These results highlight the potential of Dirac semimetals like Pt3Sn as scalable and efficient spin sources, facilitating the development of low-power, high-density spintronic memory and logic devices.