Coherent Heavy Quasiparticles in a CePt5 Surface Alloy

We report on the results of a high-resolution angle-resolved photoemission study on the ordered surface alloy CePt5. The temperature dependence of the spectra show the formation of the coherent low-energy heavy-fermion band near the Fermi level. These experimental data are supported by a multiband model calculation in the framework of the dynamical mean-field theory.