title: Breakup of quasiparticles in thin-film quantum wells.
abstract: Quantum well states in thin films are commonly described in terms of a quasiparticle confined in a quantum box, but this single-particle picture can fail dramatically near a substrate band edge, as shown by this angle-resolved photoemission study. Atomically uniform Ag films are prepared on Ge(111) to facilitate accurate line shape and dispersion relation measurements. A quantum well peak is observed to split into two peaks near the Ge valence band edge. The unusual line shapes are shown to be due to many-body interactions and are quantitatively explained by a Green's function calculation.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA.
authors.forename: S-J
authors.initials: SJ
authors.lastname: Tang
authors.forename: L
authors.initials: L
authors.lastname: Basile
authors.forename: T
authors.initials: T
authors.lastname: Miller
authors.forename: T-C
authors.initials: TC
authors.lastname: Chiang