Photoemission study of the Li/Ge(1 1 1)–3 × 1 reconstruction

• Published in: Surface science 2009, Vol.603 (4), p.727-735
• Main Authors: Gurnett, M., Holleboom, L.J., Zhang, H.M., Johansson, L.S.O.
• Format: Article
• Language: English
• Subjects: Angle-resolved photoemission; Density functional calculations; Electronic structure; Fysik; Germanium; Lithium; Physics; Surface structure; Synchrotron radiation photoelectron spectroscopy; Synchrotron radiation photoelectron spectroscopy Angle-resolved photoemission Density functional calculations Surface structure Electronic structure Germanium Lithium
• ISSN: 0039-6028; 1879-2758; 1879-2758
• DOI: 10.1016/j.susc.2009.01.019

In this article we report our findings on the electronic structure of the Li induced Ge(1 1 1)–3 × 1 reconstruction as determined by angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) and core-level spectroscopy using synchrotron radiation. The results are compared to the theoretical honeycomb-chain-channel (HCC) model for the 3 × 1 reconstruction as calculated using density functional theory (DFT). ARUPS measurements were performed in both the Γ ¯ - M ¯ and Γ ¯ - K ¯ directions of the 1 × 1 surface Brillouin zone at photon energies of 17 and 21.2 eV. Three surface related states were observed in the Γ ¯ - K ¯ direction. In the Γ ¯ - M ¯ direction, at least two surface states were seen. The calculated band structure using the single-domain HCC model for Li/Ge(1 1 1)–3 × 1 was in good agreement with experiment, allowing for the determination of the origin of the experimentally observed surface states. In the Ge 3 d core-level spectra, two surface related components were identified, both at lower binding energy with respect to the Ge 3 d bulk peak. Our DFT calculations of the surface core-level shifts were found to be in fair agreement with the experimental results. Finally, in contrast to the Li/Si(1 1 1)–3 × 1 case, no double bond between Ge atoms in the top layer was found.