We show that the dynamical screening of the Coulomb interaction among Cu-d electrons in high-Tc cuprates is very strong and that a proper treatment of this effect is essential for a consistent description of the electronic structure. In particular, we find that ab-initio calculations for undoped La2CuO4 yield an insulator only if the frequency dependence of the Coulomb interaction is taken into account. We also identify a collective excitation in the screened interaction at 9 eV which is rather localized on the copper site, and which is responsible for a satellite structure at energy -13 eV, located below the p bands.
@article{arxiv.1411.3952,
title = {Dynamical screening in La2CuO4},
author = {Philipp Werner and Rei Sakuma and Fredrik Nilsson and Ferdi Aryasetiawan},
journal= {arXiv preprint arXiv:1411.3952},
year = {2015}
}