Stable vortex configurations in superconducting 2×2 antidot clusters

Abstract

The vortex state of superconducting 2×2 antidot clusters has been studied by transport measurements. Characteristic oscillations have been observed in the magnetoresistance and superconducting-normal phase boundary at specific values of the magnetic flux Φ coming from the formation of stable vortex configurations. In analogy with semiconducting 2×2 quantum dot systems, a bistable diagonal state, perspective for single flux quantum logic applications, has been identified at half-flux filling, Φ/Φ0=0.5, where Φ0=h/2e is the flux quantum.