Spin relaxation in persistent spin textures

Spin relaxation due to the combined diffuse scattering and spin-orbit coupling (SOC) plays a crucial role for the efficient spin transport, which is a prerequisite for spintronic devices. Here, we investigate the spin relaxation in two-dimensional systems with different types of SOC, with a particular focus on the SOC with persistent spin texture (PSO). Based on the Boltzmann transport theory, we calculate spin diffusion matrices within the framework of Dyakonov-Perel mechanism. In the uniform case, it is found that the in-plane and out-of-plane spin relaxations for all considered SOCs are independent. Interestingly, the in-plane spin relaxation for certain PSOs reveals significant anisotropy characterized by the infinite spin relaxation time for the spin oriented along the direction of spin-orbit field. In the non-uniform case, we show that there always exists the static solution for the PSO with SU(2) symmetry, which corresponds the persistent spin helix in real space. Our work is expected to enrich the fundamental understanding of spin relaxation mechanism and provide new guidelines to design spin-orbitronic devices.