Universal Design Principles for High-Quality Persistent Spin Textures

Abstract: Persistent spin texture (PST) describes a unique spin-momentum locking in momentum space that maintains a uniform spin orientation through portions of the Brillouin zone (BZ), enabling exceptionally long spin lifetimes which are essential for applications in spintronics. However, materials exhibiting large BZ regions of high-quality PST, characterized by minimal spin deviation and long spin lifetimes, remain scarce. Here a universal model is introduced to capture the formation of superior PST regions arising from the interplay of spin-orbit fields at different k points. Within this framework, high-quality PSTs are identified in several systems belonging to various point groups. Notably, the nonpolar-chiral compound Na2Sn2O3 exhibits ~0.02 Å-2 high-quality PST region, which can be reversed by the switching of geometric chirality, while AgClO4 (D2d symmetry) exhibits a 0.016 Å-2 PST region. Significantly, Na2Sn2O3 and AgClO4 host persistent spin helices with spin lifetimes of 0.5-7.4 ns and 0.9-2.5 ns, respectively, among the longest reported for PST materials. In addition, both chemical substitutions and the application of pressure are demonstrated as effective routes for engineering high-quality PST. Our findings not only establish a universal principle for high-quality PST, but also provide promising materials across various point groups for the next-generation spintronic devices.