RT Journal Article T1 Periodicity and thickness effects in the cross section of quantum well states A1 Mugarza, A. A1 Ortega, J. E. A1 Mascaraque Susunaga, Arantzazu A1 Michel, E. G. A1 Altmann, K. N. A1 Himpsel, F. J. AB The photoemission cross section of quantum well states in very thin Cu films has been analyzed as a function of photon energy within a wide energy range. We show that this cross section is periodical in k space, peaking around vertical transitions of the respective Cu bulk band. The cross section peak width is analyzed in terms of final- and initial-state wave vector broadening. The latter can only be detected at low kinetic energies due to reduction of final state broadening. The initial state k(perpendicular to) broadening increases when the Cu film gets thinner, as simply expected from the uncertainty principle. PB American Physical Society SN 1098-0121 YR 2000 FD 2000-11-15 LK https://hdl.handle.net/20.500.14352/59410 UL https://hdl.handle.net/20.500.14352/59410 LA eng NO © 2000 The American Physical Society.J.E.O. and A. Mu. are supported by the Max-Planck Research Award and the Universidad del País Vasco (Projects -EUPV057.240A197/97 and 026/98). E.G.M. and A. Ma. are funded by the Spanish DGES (PB-970031) and the Comunidad de Madrid (07N/0031/1998). Experiments at ELETTRA have been performed within the TMR program under Contract No. ERBFMGECT950022. Experiments at SRC were supported by NSF under Grant No. DMR-9704196, No. DMR-9815416, and No. DMR-9531009 (Synchrotron Radiation Center, University of Wisconsin-Madison). We acknowledge the technical support from the staff of the VUV beam line at Elettra as well as helpful discussions with P.M. Echenique. NO Universidad del País Vasco NO Spanish DGES NO Comunidad de Madrid NO TMR program NO NSF NO Max-Planck Research Award DS Docta Complutense RD 15 dic 2025