ELECTRONIC-ENERGY BANDS OF BI2+XSR2-XCAN-1CUNO2N+4

Band structure, first principles, LMTO full-potential calculations within the LDA are performed and compared with experimental photoemission results for the n=1 and n=2 compounds. Close to the Fermi energy and centered around the (M) over bar point of the Brillouin zone, the experiments show an extended k-space region with very flat copper oxygen bands with small bismuth contribution. The position of the calculated LDA bands with respect to the Fermi energy and the dispersion is very dependent on the different occupations of Bi and Sr sites in the crystallographic structure, observed by x-ray studies. This is simulated in our calculations and the results seem to improve agreement with experiments.