Ab initio calculations of the dynamical response of copper

TL;DR

This paper uses ab initio calculations to explore how localized d-electrons influence copper's dynamical response, revealing features consistent with experimental optical data and analyzing scattering behaviors.

Contribution

It introduces a detailed ab initio approach to study copper's dynamical response, emphasizing the role of d-electrons and comparing RPA and TDLDA methods.

Findings

D-electrons lower the plasma frequency and cause a double-peak structure in the dynamical structure factor.

Results agree with experimental optical response data.

Analysis of dynamical scattering cross sections dependence on momentum transfer.

Abstract

The role of localized $d$-bands in the dynamical response of Cu is investigated, on the basis of {\em ab initio} pseudopotential calculations. The density-response function is evaluated in both the random-phase approximation (RPA) and a time-dependent local-density functional approximation (TDLDA). Our results indicate that in addition to providing a polarizable background which lowers the free-electron plasma frequency, d-electrons are responsible, at higher energies and small momenta, for a double-peak structure in the dynamical structure factor. These results are in agreement with the experimentally determined optical response of copper. We also analyze the dependence of dynamical scattering cross sections on the momentum transfer.