Dynamical response function of a compressed lithium monolayer

TL;DR

This paper investigates how the dynamical response function of a lithium monolayer changes under pressure using ab initio calculations, revealing new features like acoustic plasmons due to increased electronic density.

Contribution

It provides the first detailed ab initio analysis of pressure-induced modifications in the dynamical response of a lithium monolayer, highlighting the emergence of acoustic plasmons.

Findings

Electronic properties are significantly modified under pressure.

Presence of intraband, interband, and acoustic plasmons.

Electronic density increase leads to characteristic plasmon features.

Abstract

Since recent both theoretical and experimental results have proved that the simple behaviour light alkaline metals present at equilibrium breaks when high pressures are applied, they have become an important object of study in Condensed Matter Physics. On the other hand, development of new techniques in the atomic manipulation allows the growth of atomic monolayers (ML's), therefore rising the interest to analyze low dimensional systems under different conditions. In particular, new \textit{ab initio} calculations performed for a lithium ML show that its electronic properties experience important modifications under pressure, which could lead to significant modifications in its dynamical response function. In this article we perform \textit{ab initio} calculations of the dynamical response function of a lithium ML analyzing its evolution with increasing applied pressure. We show that besides the well known intraband and interband plasmons, rising electronic density induces characteristic features of acoustic plasmons related to the presence of two types of carriers at the Fermi level.