Robust anomalous metallic states and vestiges of self duality in two-dimensional granular In-InOx composites

Abstract

Many experiments investigating magnetic field tuned superconductor-insulator transition (H-SIT), often exhibit low-temperature resistance saturation, which is interpreted as an anomalous metallic phase emerging from a "failed superconductor," thus challenging conventional theory. Here we study a random granular array of indium islands grown on a gateable layer of indium-oxide. By tuning the intergrain couplings, we reveal a wide range of magnetic fields where resistance saturation is observed, under conditions of careful electromagnetic filtering and within a wide range of linear response. Exposure to external broadband noise or microwave radiation is shown to strengthen the tendency of superconductivity, where at low field a global superconducting phase is restored. Increasing magnetic field unveils an "avoided H-SIT," that exhibits granularity-induced logarithmic divergence of the resistance/conductance above/below that transition, pointing to possible vestiges of the original emergent duality observed in a true H-SIT. We conclude that anomalous metallic phase is intimately associated with inherent inhomogeneities, exhibiting robust behavior at attainable temperatures for strongly granular two-dimensional systems.

14 pages, 12 figures; after minor revision and error corrections

References in corpus (9)

• Nature of the superconductor-insulator transition in disordered superconductors
• Theory of quantum metal to superconductor transitions in highly conducting systems
• Magnetically Induced Metallic Phase in Superconducting Tantalum Films
• Quantum Metallicity on the High-Field Side of the Superconductor-Insulator Transition
• Particle-hole symmetry reveals failed superconductivity in the metallic phase of two-dimensional superconducting films
• Extreme sensitivity of the vortex state in a-MoGe films to radio-frequency electromagnetic perturbation
• Superconductor-insulator transitions in three-dimensional indium-oxide at high pressures
• Dissipative phases across the superconductor-to-insulator transition
• The discovery, disappearance and re-emergence of radiation-stimulated superconductivity

Cited by in corpus (9)

• Quantum phase transitions in two-dimensional superconductors: a review on recent experimental progress
• Anomalous metals: from "failed superconductor" to "failed insulator"
• Magnetic field induced transition from a vortex liquid to Bose metal in ultrathin a-MoGe thin film
• Flux-flow instability across Berezinskii Kosterlitz Thouless phase transition in KTaO${}_3$ (111) based superconductor
• The Berezinskii-Kosterlitz-Thouless Transition and Anomalous Metallic Phase in a Hybrid Josephson Junction Array
• Extended strange metal regime from superconducting puddles
• Critical anomalous metals near superconductivity in models with random interactions
• Voltage-tuned anomalous-metal to metal transition in hybrid Josephson junction arrays
• Gapless superconductivity in the low-frequency electrodynamic response of two-dimensional granular In/InO${}_x$ composites