4 research outputs found
Analysis of the valence-band photoemission spectrum of Sr2CuO2Cl2 along the high-symmetry directions
Band structure calculations have been used to identify the different bands
contributing to the polarisation-dependent photoemission spectra of the undoped
model cuprate SrCuOCl at the high-symmetry points of the CuO
plane , and and along the high-symmetry
directions and . Results from
calculations within the local density approximation (LDA) have been compared
with calculations taking into account the strong electron correlations by
LDA+U, with the result that the experimental order of energy levels at the
high-symmetry points is better described by the LDA+U calculation than by the
simple LDA. All the main peaks in the photoemission spectra at the high
symmetry points could be assigned to different Cu 3 and O 2 orbitals
which we have classified according to their point symmetries. The dispersions
along the high-symmetry directions were compared with an 11-band tight-binding
model which was fitted both to the LDA+U band structure calculation and the
angle-resolved photoemission data. The mean field treatment successfully
describes the oxygen derived bands but shows discrepancies for the copper ones.Comment: 13 pages, 16 figures, 5 table