  We report growth, electronic structure and superconductivity of ultrathin
epitaxial CoSi2 films on Si(111). At low coverages, preferred islands with 2, 5
and 6 monolayers height develop, which agrees well with the surface energy
calculation. We observe clear quantum well states as a result of electronic
confinement and their dispersion agrees well with density functional theory
calculations, indicating weak correlation effect despite strong contributions
from Co 3d electrons. Ex-situ transport measurements show that
superconductivity persists down to at least 10 monolayers, with reduced Tc but
largely enhanced upper critical field. Our study opens up the opportunity to
study the interplay between quantum confinement, interfacial symmetry breaking
and superconductivity in an epitaxial silicide film, which is technologically
relevant in microelectronics.
