Optical weights and waterfalls in doped charge-transfer insulators: A local density approximation and dynamical mean-field theory study of La_2−xSr_xCuO₄

We use the local density approximation in combination with the dynamical mean-field theory to investigate intermediate energy properties of the copper oxides. We identify coherent and incoherent spectral features that result from doping a charge-transfer insulator, namely quasiparticles, Zhang-Rice singlet band, and the upper and lower Hubbard bands. Angle resolving these features, we identify a waterfall-like feature between the quasiparticle part and the incoherent part of the Zhang-Rice band. We investigate the asymmetry between particle and hole doping. On the hole-doped side, there is a very rapid transfer of spectral weight upon doping in the one particle spectra. The optical spectral weight increases superlinearly on the hole-doped side in agreement with experiments.