Superconducting Proximity Effect in Quantum Dots

定义良好且可控的纳米结构，如量子点，是研究库仑相互作用、非平衡和集体有序相互作用的理想模型系统。我们从理论上研究了包含相互作用的量子点与超导引线耦合的系统中的电子输运。超导关联是由平衡和非平衡邻近效应在量子点上诱导的，可以通过栅极电压和偏置电压来控制。它们影响输运特性，例如约瑟夫森或局部和非局部安德列夫电流。对于含有非共线磁性的混合系统，可以诱导出非常规的超导配对。本项目的主要目标是开发和应用适当考虑到库仑相互作用在量子点中所起的重要作用的理论工具。我们将为不同的器件几何形状识别传输量(如电流和电流噪声)中感应常规和非常规超导关联的特征。

Well-defined and -controllable nanostructures such as quantum dots are ideal model systems to investigate the interplay of Coulomb interaction, nonequilibrium, and collective order. We study theoretically electronic transport through systems containing interacting quantum dots coupled to superconducting leads. Superconducting correlations are induced on the quantum dots by the equilibrium and nonequilibrium proximity effect and can be manipulated via gate and bias voltages. They affect the transport characteristics, e.g., of the Josephson or the local and the nonlocal Andreev currents. For hybrid systems involving noncollinear magnetism, unconventional superconducting pairing can be induced. The main objective of the present project is to develop and apply theoretical tools that properly take into account the important role played by Coulomb interaction in the quantum dot. We will identify for various device geometries signatures of the induced conventional and unconventional superconducting correlations in transport quantities such as the current and the current noise.