Enhanced Cooper pairing versus suppressed phase coherence shaping the superconducting dome in coupled aluminum nanograins
Enhanced Cooper pairing versus suppressed phase coherence shaping the superconducting dome in coupled aluminum nanograins
The development of the fundamental superconducting (SC) energy scales---the SC energy gap $\mathrm{\ensuremath{\Delta}}$ and the superfluid stiffness $J$---of granular aluminum, i.e., thin films composed of coupled nanograins, is studied by means of optical THz spectroscopy. Starting from well-coupled grains, $\mathrm{\ensuremath{\Delta}}$ grows as the grains are progressively decoupled, causing the unconventional …