Determination of an effective one-electron spectrum from the plasmon dispersion of nearly optimally doped Bi2Sr2CaCu2O8

An effective electronic one-particle spectrum of the CuO2 planes in nearly optimally doped Bi2Sr2GaCu2O8 is determined by a method analyzing plasmon d ispersion data obtained in electron energy-loss experiments in the normal s tate. The resulting effective spectrum yields a Fermi surface with the corr ect topology and which is in remarkable quantitative agreement with that ob tained in recent photoemission experiments. In spite of its simplicity the effective model spectrum agrees well with the noninteracting parts of the a ntibonding Cu-O band as obtained in band-structure calculations based on th e local-density approximation. The results indicate that in contrast to oth er experiments in such systems strong correlation effects are of minor impo rtance for the: plasmon dispersion. Additionally, the method yields also th e background dielectric constant. The proposed method is applicable to othe r low-dimensional systems. [S0163-1829(99)11625-4].