Structural investigation of the quasi-one-dimensional reconstructions induced by Eu adsorption on a Si(111) surface
2005 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 72, no 19, 195342- p.Article in journal (Refereed) Published
The surface structures of the (quasi-)one-dimensional reconstructions induced by the adsorption of Eu on Si(111) have been investigated by low-energy electron diffraction (LEED) and high-resolution core-level photoelectron spectroscopy. Different phases were observed in LEED depending on the Eu coverage. The lowest coverage phase has a (3×2) periodicity, and the highest coverage phase has a (2×1) one. Of the intermediate phases, the LEED pattern of the so-called (5×1) surface indicates that this surface has actually a (5×4) periodicity. The Eu 4f core-level spectra show that the Eu coverages of the (3×2), (5×4), and (2×1) phases are 1∕6 monolayer (ML), 0.3 ML, and 0.5 ML, respectively, and that the valence state of the adsorbate is 2+ in all these three phases. In the Si 2p core-level spectra, three surface components were observed in both the lowest and highest coverage phases. By considering the energy shift and intensity of each surface component, we conclude that the structure of the (3×2) phase is basically the same as that of the honeycomb-chain-channel model, and that the (2×1) phase is formed by π-bonded Seiwatz Si chains. Regarding the (5×4) phase, two extra Si 2p surface components were observed together with the three components observed in the two end phases. Taking the energy shifts and intensities of the extra surface components into account, we propose a structural model of the (5×4) phase.
Place, publisher, year, edition, pages
2005. Vol. 72, no 19, 195342- p.
IdentifiersURN: urn:nbn:se:liu:diva-39512DOI: 10.1103/PhysRevB.72.195342ISI: 000233603700109Local ID: 49085OAI: oai:DiVA.org:liu-39512DiVA: diva2:260361