Emergent Anomalous Metallic State in a Fully Superconducting Island Array

Anomalous metallic states represent a regime in which a system resists both full superconductivity and conventional metallic behavior, instead exhibiting a finite resistivity plateau as temperature approaches zero. Often described as "failed superconductors," these states challenge the long-held dichotomy between superconducting and metallic ground states and raise questions about the role of quantum coherence and dissipation in low-dimensional systems. While such behavior is typically observed near the superconductor-insulator transition, where phase fluctuations suppress global coherence, we instead find similar signatures in a system that remains fully superconducting at zero field. In arrays of niobium islands coupled across gold substrates, field cooling under a perpendicular magnetic field produces finite-resistance plateaus associated with incommensurate vortex configurations. These plateaus are asymmetric around commensurate field values, revealing a vortex particle-hole asymmetry. The observed behavior can be interpreted within a vortex creep framework, extending the understanding of anomalous metallicity to strongly superconducting systems.