Spatially resolved quantum plasmon modes in metallic nano-films from first principles
Abstract
Electron energy loss spectroscopy (EELS) can be used to probe plasmon excitations in nanostructured materials with atomic-scale spatial resolution. For structures smaller than a few nanometers quantum effects are expected to be important, limiting the validity of widely used semi-classical response models. Here we present a method to identify and compute spatially resolved plasmon modes from first principles based on a spectral analysis of the dynamical dielectric function. As an example we calculate the plasmon modes of 0.5-4 nm thick Na films and find that they can be classified as (conventional) surface modes, sub-surface modes, and a discrete set of bulk modes resembling standing waves across the film. We find clear effects of both quantum confinement and non-local response. The quantum plasmon modes provide an intuitive picture of collective excitations of confined electron systems and offer a clear interpretation of spatially resolved EELS spectra.
Cite
@article{arxiv.1301.0184,
title = {Spatially resolved quantum plasmon modes in metallic nano-films from first principles},
author = {Kirsten Andersen and Karsten W. Jacobsen and Kristian S. Thygesen},
journal= {arXiv preprint arXiv:1301.0184},
year = {2013}
}
Comments
7 pages, 7 figures