Vortex states in nanoscale superconducting squares: the influence of quantum confinement

Abstract

Bogoliubov-de Gennes theory is used to investigate the effect of the size of a superconducting square on the vortex states in the quantum confinement regime. When the superconducting coherence length is comparable to the Fermi wavelength, the shape resonances of the superconducting order parameter have strong influence on the vortex configuration. Several unconventional vortex states, including asymmetric ones, giant multi-vortex combinations, and states comprising giant antivortex, were found as ground states and their stability was found to be very sensitive on the value of $k_F{\xi }_0$, the size of the sample $W$, and the magnetic flux $\Phi$. By increasing the temperature and/or enlarging the size of the sample, quantum confinement is suppressed and the conventional mesoscopic vortex states as predicted by the Ginzburg-Laudau (GL) theory are recovered. However, contrary to the GL results we found that the states containing symmetry-induced vortex-antivortex pairs are stable over the whole temperature range. It turns out that the inhomogeneous order parameter induced by quantum confinement favors vortex-antivortex molecules, as well as giant vortices with a rich structure in the vortex core - unattainable in the GL domain.

References in corpus (16)

• Bipolar supercurrent in graphene
• Observation of shell effects in superconducting nanoparticles of Sn
• Attojoule calorimetry of mesoscopic superconducting loops
• Symmetric and non-symmetric vortex-antivortex molecules in fourfold superconducting geometry
• Magnetic-field induced quantum-size cascades in superconducting nanowires
• Vortex states in mesoscopic superconducting squares: Formation of vortex shells
• Effect of the boundary condition on the vortex patterns in mesoscopic three-dimensional superconductors - disk and sphere
• Unconventional vortex states in nanoscale superconductors due to shape-induced resonances in the inhomogeneous Cooper-pair condensate
• Superconducting proximity effect in graphene under inhomogeneous strain
• Dynamics of Vortex Nucleation in Nanomagnets with Broken Symmetry
• Stabilization of vortex-antivortex configurations in mesoscopic superconductors by engineered pinning
• Thermal signatures of Little-Parks effect in the heat capacity of mesoscopic superconducting rings
• Continuum versus discrete flux behaviour in large mesoscopic Bi(2)Sr(2)CaCu(2)O(8+delta) disks
• Multiple Vortex Cores in 2D Electronic Systems with Proximity Induced Superconductivity
• Model for Vortex Pinning in a Two-Dimensional Inhomogeneous d-wave Superconductor
• Thermally Assisted Penetration and Exclusion of Single Vortex in Mesoscopic Superconductors

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