Abstract: Multi-layer n- and p-type Si thin film structures are presented which are configured with through-thickness strain gradients in order to take advantage of flexoelectric polarization and achieve Rashba SOC at Si interfaces. In freestanding thin films, through-thickness strain gradients can be achieved due to differential thermal expansion. In on-substrate thin films, through-thickness strain gradients can be achieved by use of a thick insulating layer. The residual stress due to the insulating layer will give rise to through-thickness strain gradients as shown in FIG. 1B. The residual stresses can be controlled using layer thickness, deposition parameters and layer material. Examples systems include MgO/(p-Si), Pd/Ni81Fe19/MgO/p-Si, Pd/Ni80Fe20/MgO/n-Si, Pd/Ni80Fe20/MgO/p-Si, and Ni80Fe20/p-Si.