Dynamical Response of Correlated Electrons in Solids Probed by Inelastic Scattering Experiments: An Ab Initio Theoretical Perspective

TL;DR

This paper uses ab initio methods to analyze the excitation spectra of correlated electrons in metals, revealing that many observed anomalies are due to band-structure effects rather than strong correlations, and discusses implications for electronic excitation theories.

Contribution

The study applies time-dependent density-functional theory and GW approximation to clarify the origins of anomalies in electron excitation spectra, offering a new perspective on electronic excitations in materials.

Findings

Anomalies in experimental data are explained by band-structure effects.

Calculated lifetimes of plasmons match experimental observations.

Electron momentum density in Li is characterized using GW approximation.

Abstract

We present results of ab initio theoretical investigations of the excitation spectra of correlated electrons in metals (Al, K, and Li) and their interplay with inelastic scattering experiments. We resolve various anomalies contained in the data, which were originally viewed as signatures of strong dynamical electronic correlations; we show that, instead, the anomalies are due to band-structure effects. The underlying theoretical framework in our density-response calculations is time-dependent density-functional theory; with this scheme we discuss the lifetime of the K plasmon, and the dynamical structure factor of Al. From a self-consistent solution of the Dyson equation in the GW approximation for the electron self-energy, we discuss the electron momentum density in Li. Our results and methods point to a new way of thinking about electronic excitations in real materials. The main challenge ahead is the proper treatment of dynamical correlations for realistic representations of the band structure.