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

Band structure, first principles, LMTO full-potential calculations wit hin 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 expe riments show an extended k-space region with very flat copper oxygen b ands with small bismuth contribution. The position of the calculated L DA bands with respect to the Fermi energy and the dispersion is very d ependent on the different occupations of Bi and Sr sites in the crysta llographic structure, observed by x-ray studies. This is simulated in our calculations and the results seem to improve agreement with experi ments.