Topological defect states in mesoscopic superconductors with mixed pairing symmetries

• Published in: The European physical journal. B, Condensed matter physics Condensed matter physics, 2021-09, Vol.94 (9), Article 193
• Main Authors: Chai, Rui-Feng, Zha, Guo-Qiao
• Format: Article
• Language: English
• Subjects: Chemical potential; Complex Systems; Condensed Matter Physics; Fluid- and Aerodynamics; Magnetic flux; Mesoscopic superconductors; P waves; Phase transitions; Physics; Physics and Astronomy; Regular Article - Solid State and Materials; Solid State Physics; Specific gravity; Superconductors; Topology
• ISSN: 1434-6028; 1434-6036
• DOI: 10.1140/epjb/s10051-021-00206-8

In the framework of the microscopic Bogoliubov–de Gennes theory, we investigate the vortex and skyrmionic states as well as phase transitions between them in mesoscopic superconducting squares with coexisted spin-triplet ( p -wave) and spin-singlet ( s -wave and d -wave) pairing symmetries. By choosing different chemical potential μ , the influence of next-nearest-neighbor hopping t ′ on the evolution of mixed pairing orders is mainly discussed. For the case of small | μ | in which the triplet p x ± i p y -wave symmetry is dominant, the skyrmionic structures containing the vortex-antivortex pair become stable at appropriate external magnetic flux. The transitions between different coreless skyrmionic modes can take place with tuning t ′ . For further enlarged | μ | , the singlet s -wave component is gradually enhanced in the present mescoscopic sample. We can obtain the transitions between different multivortex states and between the multivortex and skyrmionic states when t ′ is varied. The corresponding zero-energy local density of states and the relative phase differences are provided to display different topological defects. Graphic abstract