EXPERIMENTAL DISPERSIONS OF CONDUCTION BANDS IN BI2CASR2CU2O8

The unoccupied electronic structure of BizCaSrzCuzOs crystals cleaved in ultrahigh vacuum has been investigated with k-resolved inverse photoelectron spectroscopy. A number of dispersing structures are observed close to the Fermi level, corresponding to rapidly dispersing Cu-0 and Bi-0 conduction bands. An expected band crossing at the Fermi level of Cu-0 bands is observed, although the bandwidth of these states is found to be much smaller than that predicted in several band structure calculations. Likewise, two Bi-0 bands are found to have less dispersion than predicted and these bands are also more separated from each other throughout the Brillouin zone. © 1990 IOP Publishing Ltd.