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.
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机译：提出了多层n型和p型Si薄膜结构，这些结构具有贯穿厚度的应变梯度，以便利用柔电极化并在Si界面处实现Rashba SOC。在独立式薄膜中，由于差异的热膨胀，可以实现贯穿厚度的应变梯度。在衬底上的薄膜中，可以通过使用厚的绝缘层来实现贯穿厚度的应变梯度。如图2所示，由绝缘层引起的残余应力将产生贯穿厚度的应变梯度。 1 B。可以使用层厚度，沉积参数和层材料来控制残余应力。示例系统包括MgO /（p-Si），Pd / Ni 81 Fe 19 / MgO / p-Si，Pd / Ni 80 Fe 20 / MgO / n-Si，Pd / Ni 80 Fe 20 / MgO / p-Si和Ni 80 Fe 20 / p-Si。
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