# Plasmon Standing Waves by Oxidation of Si(553)-Au

## TL;DR

This study examines how oxidation affects the plasmonic properties of Au atomic wires on Si(553), revealing that oxidation mainly impacts the Si environment with minimal effect on plasmon dispersion, leading to standing wave formation.

## Contribution

It demonstrates that oxidation introduces scattering centers causing standing waves without opening an electronic gap in Au atomic wires on Si(553).

## Key findings

- Oxidation affects only the Si environment, not the Au wires.
- Plasmon dispersion remains largely unchanged by oxidation.
- Standing waves form on small wire sections due to oxygen-induced scattering.

## Abstract

Self-assembled Au atomic wires on stepped Si surfaces are metallic, as evidenced by a one-dimensionally dispersing plasmonic excitation. Here we investigate the effects of oxidization on metallicity along such Au atomic wires on a regularly stepped Si(553) surface, by employing infrared absorption and high resolution electron energy loss spectroscopies. Our results indicate that only the Si environment undergoes oxidation, which has a remarkably small effect on the plasmon dispersion. Only close to $k_{\parallel}\rightarrow 0$ the plasmon dispersion ends at increasingly higher energies as a function of oxygen exposure, which is attributed to standing wave formation on small sections of Au wires generated by the introduction of O atoms as scattering centers, not to electronic gap opening. This interpretation is in full agreement with the findings by infrared spectroscopy and with low energy electron diffraction.