We investigate the physical mechanisms for achieving an electrical control of conventional spin-singlet superconductivity in thin films by focusing on the role of surface orbital polarization. Assuming a multiorbital description of the metallic state, due to screening effects the electric field acts by modifying the strength of the surface potential and, in turn, yields nontrivial orbital Rashba couplings. The resulting orbital polarization at the surface and in its close proximity is shown to have a dramatic impact on superconductivity. We demonstrate that, by varying the strength of the electric field, the superconducting phase can be either suppressed, i.e., turned into normal metal, or undergo a 0-$\pi$ transition with the $\pi$ phase being marked by nontrivial sign change of the superconducting order parameter between different bands. These findings unveil a rich scenario to design heterostructures with superconducting orbitronics effects.

中文翻译：

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通过表面轨道极化实现电可调式超导

我们通过关注表面轨道极化的作用，研究了实现薄膜中常规自旋单极超导的电控制的物理机制。假设对金属状态的多轨道描述，由于屏蔽效应，电场通过改变表面电势的强度起作用，进而产生非平凡的轨道Rashba耦合。结果表明，在表面及其附近产生的轨道极化对超导性产生了巨大影响。我们证明，通过改变电场强度，可以抑制超导相，即转变为普通金属，或经历0-$\pi$ 与过渡 $\pi$通过在不同频带之间超导阶数参数的非平凡符号变化来标记相位。这些发现揭示了设计具有超导双电子效应的异质结构的丰富场景。