Exploring the impact of core expansion on the vortex distribution in superconducting–normal-metal hybrid nanostructures
Authors: Ritika Panghotra, Matias Timmermans, Cun Xue, Bart Raes, Victor Moshchalkov and Joris Van de Vondel
Phys. Rev. B 100, 054519
Abstract: The superconducting condensate in a bilayer normal-metal–superconducting film has a nonuniform dependence throughout the layer. For sufficiently thin normal metallic films, the superconducting correlations induced by the contacting superconducting layer result in the formation of a minigap and the characteristic length scales governing the response of the condensate will be different. In this work we use scanning tunneling spectroscopy to visualize the vortex states as a function of the applied magnetic field in a Au-MoGe nanostructure. By comparing the obtained zero-bias conductance maps with time-dependent Ginzburg-Landau simulations, we directly confirm that the observed vortex distributions can only be explained by taking into account the impact of the normal metallic layer. We illustrate this impact on the vortex state for two lithographically fabricated mesoscopic bilayer structures containing an identical antidot array but having different lateral sizes.