  The superconducting critical temperature, TC, of thin Nb films is
significantly modified when gold nanoparticles (NPs) are chemically linked to
the Nb film, with a consistent enhancement when using 3 nm long disilane linker
molecules. The TC increases by up to 10% for certain linker length and NPs
size. No change is observed when the nanoparticles are physisorbed with
non-linking molecules. Electron tunneling spectra acquired on the linked NPs
below TC typically exhibit zero-bias peaks. We attribute these results to a
pairing mechanism coupling electrons in the Nb and the NPs, mediated by the
organic linkers.
