Ab Initio Evaluation of Plasmon Lifetimes in the Alkali Metals

TL;DR

This paper uses ab initio calculations to analyze plasmon linewidth dispersion in alkali metals, revealing decay mechanisms and emphasizing the importance of first-principles methods for understanding electronic excitations.

Contribution

It demonstrates that plasmon linewidth dispersion in potassium is mainly due to decay into particle-hole excitations, providing new insights into lithium's plasmon behavior.

Findings

PLD in K is dominated by decay into particle-hole excitations.

Ab initio results highlight the role of d-symmetry states in plasmon decay.

The study underscores the importance of first-principles methods for electronic excitation analysis.

Abstract

The anomalous plasmon linewidth dispersion (PLD) measured in K by vom Felde, Sprosser-Prou, and Fink (Phys. Rev. B 40, 10181 (1989)), has been attributed to strong dynamical electron-electron correlations. On the basis of ab initio response calculations, and detailed comparison with experiment, we show that the PLD of K is, in fact, dominated by decay into particle-hole excitations involving empty states of d-symmetry. For Li, we shed new light on the physics of the PLD. Our all-electron results illustrate the importance of ab initio methods for the study of electronic excitations.