INFLUENCE OF DOPING ON THE ELECTRONIC-STRUCTURE OF (LA,SR)2CUO4

High-statistics (>4 x 10(8) counts), room-temperature measurements of the electron-positron momentum density of La2-xSrxCuO4 have been perfo rmed for samples with Sr concentrations of x = 0.0, 0.1, 0.13, and 0.2 . These spectra have been analyzed in conjunction with theoretical cal culations of the electron-positron momentum density. The metallic samp les show features consistent with the presence of a Fermi surface, but its evolution with increasing Sr concentration does not follow the pr edictions of band theory. These results may indicate the effects of el ectron-electron correlation on the electron momentum distribution in t he Cu-O plane.