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

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 $k_{\parallel }\to 0$ 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.

12 pages, 8 figures

References in corpus (4)

• Theory of surface plasmons and surface-plasmon polaritons
• Intrinsic magnetism at silicon surfaces
• Systematic investigation of the structure of the Si(553)-Au surface from first principles
• Direct momentum-resolved observation of one-dimensional confinement of externally doped electrons within a single subnanometre-scale wire