Supercurrent Distribution in Real-Space and Anomalous Paramagnetic Response in a Superconducting Quasicrystal

Abstract

We theoretically study the real-space distribution of the supercurrent that flows under a uniform vector potential in a two-dimensional quasiperiodic structure. This is done by considering the attractive Hubbard model on the quasiperiodic Ammann-Beenker structure and studying the superconducting phase within the Bogoliubov-de Gennes mean-field theory. Decomposing the local supercurrent into the paramagnetic and diamagnetic components, we numerically investigate their dependencies on average electron density, temperature, and the angle of the applied vector potential. We find that the diamagnetic current locally violates the current conservation law, necessitating compensation from the paramagnetic current, even at zero temperature. The paramagnetic current shows exotic behaviors in the quasiperiodic structure, such as local currents which are oriented transversally or reversely to that of the applied vector potential.

14 pages, 11 figures

References in corpus (8)

• Commensurability effects in superconducting Nb films with quasiperiodic pinning arrays
• Superconductivity on a Quasiperiodic Lattice: Extended-to-Localized Crossover of Cooper Pairs
• Conventional superconductivity in quasicrystals
• Enhanced pinning and proliferation of matching effects in a superconducting film with a Penrose array of magnetic dots
• Physical properties of weak-coupling quasiperiodic superconductors
• Superlattice structure in the antiferromagnetically ordered state in the Hubbard model on the Ammann-Beenker tiling
• Enhancing the critical current in quasiperiodic pinning arrays below and above the matching magnetic flux
• Pair-breaking of multi-gap superconductivity under parallel magnetic fields in electric-field-induced surface metallic state