Surface effects on the electronic energy loss of charged particles entering a metal surface

TL;DR

This paper investigates how surface effects influence the electronic energy loss of charged particles entering metals, highlighting the impact of boundary effects and electron-density profiles using advanced theoretical methods.

Contribution

It introduces a detailed analysis of surface effects on energy loss using linear-response and time-dependent density functional theory, emphasizing the role of electron-density profiles.

Findings

Boundary effects significantly alter loss spectra.

Non-abrupt electron-density profiles impact surface excitations.

Surface and bulk modes are orthogonal, affecting energy loss mechanisms.

Abstract

Surface effects on the electronic energy loss of charged particles entering a metal surface are investigated within linear-response theory, in the framework of time-dependent density functional theory. Interesting phenomena occur in the loss spectra originated by the boundary (bregenzung) effect, which is as a consequence of the orthogonality of surface and bulk excitation modes. Our calculations indicate that the presence of a non-abrupt electron-density profile at the surface severely affects the nature of surface excitations, as deduced from comparison with simplified models.