Crystal momentum dependence of the correlation satellite intensity in the resonant photoemission spectra of

¹ INFM and Sincrotrone Trieste S.S. 14 Km. 163.5 in Area Science Park, 34012 Trieste, Italy
² INFM and Dipartimento di Fisica dell'Università di Modena Via G. Campi 132/A, 41100 Modena, Italy
³ INFM and Dipartimento di Fisica dell'Università di Pavia - Via Bassi, Pavia, Italy
⁴ INFM and Dipartimento di Fisica dell'Università Cattolica di Brescia Via Trieste 17, 25121 Brescia, Italy
⁵ LURE, Bat. 209D, Université Paris-Sud, F-91405 Orsay, France and Instituto de Ciencia de Materiales, CSIC - 28049 Madrid, Spain
⁶ LURE, Bat. 209D, Université Paris-Sud - F-91405 Orsay, France

Corresponding author: delpennino@unimo.it

Received: 7 May 1999
Accepted: 15 February 2000

Abstract

Angle-resolved resonant photoemission measurements at the threshold have been performed on the superconducting cuprate . We have investigated in particular the correlation satellite appearing in the valence band photoemission spectrum to investigate the effect of solid state on the interference effect occurring at resonance. We found that the intensity of the correlation satellite changes with the electron take-off angle in a way that depends on the particular crystallographic direction and on the sample hole doping. These results indicate that the intensity enhancement at the absorption edge is a real resonance albeit the intermediate state in the autoionization process is partly delocalised. This fact does not prevent the occurrence of interference between indirect and direct photoemission.