Dynamical screening in La2CuO4

TL;DR

This paper demonstrates that dynamical screening significantly influences the electronic structure of La2CuO4, showing that proper frequency-dependent Coulomb interactions are crucial for accurate ab-initio insulating state predictions.

Contribution

It reveals the importance of including dynamical screening effects in ab-initio calculations of high-Tc cuprates, highlighting a localized collective excitation at 9 eV.

Findings

Dynamical screening is very strong in La2CuO4.

Proper treatment of frequency dependence is essential for insulating behavior.

A localized collective excitation at 9 eV causes a satellite at -13 eV.

Abstract

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.