High-resolution core-level photoemission study of Eu-induced (3x2)/(3x4) reconstruction on Ge(111)

Journal Article · Fri Sep 15 04:00:00 EDT 2006 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.74.115320· OSTI ID:20853667

Kuzmin, M; Peraelae, R E; Laukkanen, P; Ahola-Tuomi, M; Vaeyrynen, I J ^[1]

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1. Department of Physics, University of Turku, FIN-20014 Turku (Finland)

We have investigated Eu-induced Ge(111)-(3x2)/(3x4) reconstruction by high-resolution core-level photoelectron spectroscopy using synchrotron radiation and low-energy electron diffraction. Recent scanning tunneling microscopy (STM) observations [Phys. Rev. B 73, 125332 (2006)] revealed that the Ge arrangement of this reconstruction can be well described in terms of the honeycomb chain-channel (HCC) geometry proposed earlier for metal/Si(111)-(3x1) and -(3x2) surfaces; the Eu atoms, however, were found to reside at two different adsorption sites in the Eu/Ge(111)-(3x2)/(3x4) reconstruction, in contrast to the equivalent adsorption sites (e.g., T4) occupied in the case of Si. The present photoemission results provide further information about the atomic arrangement of Eu/Ge(111)-(3x2)/(3x4). In particular, we show that the Ge 3d core-level data cannot be interpreted by the HCC structure with the Eu atoms adsorbed only on T4 sites, giving a spectroscopic support for the suggestions based on the earlier STM data. We consider here a modified HCC-based configuration for the Eu/Ge(111)-(3x2)/(3x4) surface where the Eu atoms occupy two different sites in the empty channel between the neighboring Ge honeycomb chains. The atomic models are discussed in the context of the Ge 3d and Eu 4f data as well as the previous results available in the literature. Finally, we propose a structural model that allows us to account for the present photoemission and earlier STM findings.

• OSTI ID: 20853667
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 11 Vol. 74; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ADSORPTION
ATOMIC MODELS
ATOMS
ELECTRON DIFFRACTION
ENERGY LEVELS
EUROPIUM
GERMANIUM
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
RESOLUTION
SCANNING TUNNELING MICROSCOPY
SEMICONDUCTOR MATERIALS
STRUCTURAL MODELS
SURFACES
SYNCHROTRON RADIATION