Abstract

Based on the spin-generalized Bogoliubov–de Gennes theory, we investigate the topological defect configurations in a mesoscopic superconducting square with spin–orbit (SO) interaction. The mixed even-parity d-wave and extended s-wave components can be obtained by suitable choice of the chemical potential in such a system. We find that several novel types of topological defect states can be generated in the presence of Rashba SO coupling when the external magnetic flux turns on. Unclosed domain-wall states carrying even or odd number of one-component vortices as well as double-quanta skyrmionic patterns can appear for different Rashba SO-coupling strengths. The next-nearest-neighbor hopping effect on the evolution of topological structures is further examined. A skyrmionic chain feature with one-component vortex–antivortex pairs can show up in the present mixed-pairing system. Our investigation may provide useful information for future experiments and shed new light on device designing.

中文翻译：

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具有 Rashba 自旋轨道相互作用的介观超导正方形中的拓扑缺陷态和相变

摘要

基于自旋广义 Bogoliubov-de Gennes 理论，我们研究了具有自旋轨道（SO）相互作用的介观超导正方形中的拓扑缺陷配置。混合偶校验d波和扩展s-wave components can be obtained by suitable choice of the chemical potential in such a system. 我们发现当外部磁通量开启时，在存在 Rashba SO 耦合的情况下可以产生几种新型拓扑缺陷态。对于不同的 Rashba SO 耦合强度，可能会出现带有偶数或奇数个单分量涡流以及双量子skyrmionic 模式的未闭合畴壁状态。进一步研究了对拓扑结构演化的次最近邻跳跃效应。具有单组分涡-反涡对的skyrmionic链特征可以出现在目前的混合配对系统中。我们的调查可能为未来的实验提供有用的信息，并为设备设计提供新的思路。