Brun, ChristopheHong, I.-PoPatthey, FrancoisSklyadneva, I. Yu.Heid, R.Echenique, P. M.Bohnen, K. P.Chulkov, E. V.Schneider, Wolf-Dieter2010-11-302010-11-302010-11-30200910.1103/PhysRevLett.102.207002https://infoscience.epfl.ch/handle/20.500.14299/60158WOS:000266309000055The energy gap Delta of superconducting Pb islands grown on Si(111) was probed in situ between 5 and 60 monolayers by low-temperature scanning tunneling spectroscopy. Delta was found to decrease from its bulk value as a function of inverse island thickness. Corresponding T-c values, estimated using bulk gap-to-T-c ratio, are in quantitative agreement with ex situ magnetic susceptibility measurements, however, in strong contrast to previous scanning probe results. Layer-dependent ab initio density functional calculations for freestanding Pb films show that the electron-phonon coupling constant, determining T-c, decreases with diminishing film thickness.Transition-TemperatureQuantum-SizeMetal-FilmsThin-FilmsPotentialsDensityEnergyLimittext::journal::journal article::research article