Phonon-induced decay of a quantum-well hole: One monolayer Na on Cu(111)

The phonon-induced decay of an overlayer quantum-well hole is investigated theoretically and considered for one monolayer of Na on Cu(111). The electron-phonon coupling matrix element is determined by a first-principles deformation potential and model potential wave functions. The main contribution to the lifetime broadening can be attributed to the electron-phonon coupling in the overlayer and interface region. Peak width and temperature dependence are consistent with photoemission data.