Quasiparticle dynamics of inhomogeneous superconducting and spin-orbit coupledsystems

在拟议的项目中，我们的目标是研究以下主题：(A)研究强无序超导体的光谱性质。几年来，由于超导-绝缘体的转变，这类系统成为了科学关注的焦点，而超导-绝缘体转变可能是在强无序状态下实现的。我们发现超导态被分离成纳米尺度的岛，在那里首先实现局域配对，然后在较低的温度下，根据无序强度，可以实现相干超导态。在建议的项目中，我们的目标是计算集体激发对这些系统光谱性质的影响，从而有助于理解超导体-绝缘体的相变。(B)与氧化物界面的自旋-电荷转换相关的研究。观察到的钛酸锶和铝酸镧两种带状绝缘体之间的金属导电性具有有趣的科学问题，但也具有很强的技术应用潜力。这些系统的特点是强烈的自旋-轨道耦合，这使得它们适合于自旋电子学的应用。事实上，最近的实验已经证明了将非平衡自旋极化转换为电流的巨大效率。我们的项目旨在基于一个微观模型来理解这种所谓的氧化物界面上的自旋-原电池效应。除了充分实现能带结构和原子自旋-轨道耦合外，还需要考虑无序效应。我们的研究还计划扩展到自旋霍尔效应，它描述了自旋电流到电流的转换。

Within the proposed project we aim to investigate the following topics:(a) Investigation of spectral properties of strongly disordered superconductors. Since several years such systems are in the focus of scientific interest due to the superconducting-insulator transition which may be realized at strong disorder. One finds a segregation of the superconducting state into nanometer size islands where first local pairing is realizedbefore at lower temperatures and depending on the disorder strength a coherent superconducting state may be realized. Within the proposed project we aim to calculate the influence of collective excitations on the spectral properties of these systems and therefore contribute to an understanding of the superconductor-insulator phase transition.(b) Investigations related to spin-charge conversion at oxide interfaces. The observed metallic conductivity between the two band insulators strontium titanate and lanthanum aluminate bears interesting scientific questions but also strong potential for technical applications.These systems are characterized by a strong spin-orbit coupling which makes them suitable for spintronics applications. In fact, recent experiments have demonstrated a large efficiencyfor the conversion of a non-equilibrium spin polarization into an electric current. Our project aims to understand this so-called spin-galvanic at oxide interfaces effect based on a microscopic model. Besides an adequate implementation of the bandstructure and atomic spin-orbit coupling it is also necessary to include the effect of disorder. Our investigations arealso planned to be extended to the spin-Hall effect which describes the conversion of a spin current into an electric current.