标题： 基于双磁杂质的约瑟夫森二极管的设计 显示英文标题

标题： Design of a Josephson diode based on double magnetic impurities

摘要： 我们理论上提出了一种基于双磁杂质的通用超导二极管器件，这些磁杂质与约瑟夫森结的连接区域耦合。 正向和反向电流流过结时会产生相反的磁场，使侧边磁杂质的磁矩翻转到相反方向，从而两个杂质会对相反电流产生不同的影响。 这导致正向和反向临界电流不相等的现象，称为超导二极管效应（SDE）。 使用非平衡格林函数方法（NEGF），我们得到了方向依赖的临界电流。 我们确认了SDE的存在，并展示了超导二极管效率对一系列参数的依赖性，包括磁矩的大小、方向和位置。 此外，我们系统地分析了系统中非互易性的对称关系。 我们的方案通过避免对外部磁场、库珀对动量和自旋轨道耦合的需求，具有很高的实用性。 我们的方法为非互易电子电路的发展开辟了新可能性，并为超导器件的进步提供了另一种视角。 显示英文摘要

摘要： We theoretically propose a universal superconducting diode device based on double magnetic impurities which are coupled to the connection region of the Josephson junction. The positive and negative currents flowing across the junction can generate opposite magnetic fields, flipping the magnetic moment of the side magnetic impurity to the opposite directions, and in turn, the two impurities will have different impacts on the opposite currents. This results in the phenomenon that the positive and negative critical currents are unequal, referred to as the superconducting diode effect (SDE). Using the nonequilibrium Green's function method (NEGF), we obtain the direction-dependent critical currents. We confirm the emergency of the SDE and demonstrate the dependence of the superconducting diode efficiency on a range of parameters including the magnitude, the direction, and the position of the magnetic moment. Besides, we systematically analyze the symmetry relations of the nonreciprocity in our system. Our proposal has high practicability by avoiding the demand on the external magnetic field, the Cooper pair momentum, and the spin-orbit coupling. Our approach opens up new possibilities for the development of nonreciprocal electronic circuits and provides an alternate perspective on the advancement of superconducting devices.