Details
| Original language | English |
|---|---|
| Pages (from-to) | 265-276 |
| Number of pages | 12 |
| Journal | Surface Science |
| Volume | 459 |
| Issue number | 3 |
| Publication status | Published - 28 Jun 2000 |
Abstract
Alkali and earth alkali metals like Li and Sr adsorbed on the furrowed substrates Mo(211) and W(211) tend to form chain structures (1 × n). These chains are oriented normal to the furrows, and n can reach values up to 8. In order to clarify the nature of the coupling along the furrows, we carried out a quantitative LEED-IV study in the energy range between 50 and 180 eV. We investigated the adsorption geometry of the Sr(1 × 5) structure on Mo(211) including the relaxations in the substrate. These results are compared with those obtained recently for the Li(1 × 4) structure on the same surface. The long-range indirect interactions between both types of adsorbate atoms that are responsible for ordering of the chains in the [01̄1] direction are correlated with substantial lateral substrate relaxations by up to 0.2 angstrom along the Mo(211) [1̄11] furrow direction. For both adsorbates, the relaxations form wave-like density modulations in the substrate that seem to be caused by Friedel oscillations of the substrate conduction electrons. These screen the local adsorbate-induced distortion of the electron density. The variation of periodicity and the corresponding change of effective screening length between the two adsorbates may be due to surface states involved in the bond formation. Whereas for Sr, the Langmuir-Gurney (LG) model still provides a consistent picture of bond formation compared with the observed bond lengths and changes of work function, the predictions of the LG model are inconsistent with the experimental findings for Li.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Materials Science(all)
- Surfaces, Coatings and Films
- Materials Science(all)
- Materials Chemistry
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In: Surface Science, Vol. 459, No. 3, 28.06.2000, p. 265-276.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Geometrical evidence for long-range coupling in strongly anisotropic adsorbate systems
T2 - Sr and Li on Mo(211)
AU - Kolthoff, D.
AU - Pfnür, Herbert
N1 - Funding information: This work was supported by the Deutsche Forschungsgemeinschaft and by the Volkswagen Stiftung. Useful discussions with A.G. Naumovets, A. Fedorus and V. Koval are gratefully acknowledged.
PY - 2000/6/28
Y1 - 2000/6/28
N2 - Alkali and earth alkali metals like Li and Sr adsorbed on the furrowed substrates Mo(211) and W(211) tend to form chain structures (1 × n). These chains are oriented normal to the furrows, and n can reach values up to 8. In order to clarify the nature of the coupling along the furrows, we carried out a quantitative LEED-IV study in the energy range between 50 and 180 eV. We investigated the adsorption geometry of the Sr(1 × 5) structure on Mo(211) including the relaxations in the substrate. These results are compared with those obtained recently for the Li(1 × 4) structure on the same surface. The long-range indirect interactions between both types of adsorbate atoms that are responsible for ordering of the chains in the [01̄1] direction are correlated with substantial lateral substrate relaxations by up to 0.2 angstrom along the Mo(211) [1̄11] furrow direction. For both adsorbates, the relaxations form wave-like density modulations in the substrate that seem to be caused by Friedel oscillations of the substrate conduction electrons. These screen the local adsorbate-induced distortion of the electron density. The variation of periodicity and the corresponding change of effective screening length between the two adsorbates may be due to surface states involved in the bond formation. Whereas for Sr, the Langmuir-Gurney (LG) model still provides a consistent picture of bond formation compared with the observed bond lengths and changes of work function, the predictions of the LG model are inconsistent with the experimental findings for Li.
AB - Alkali and earth alkali metals like Li and Sr adsorbed on the furrowed substrates Mo(211) and W(211) tend to form chain structures (1 × n). These chains are oriented normal to the furrows, and n can reach values up to 8. In order to clarify the nature of the coupling along the furrows, we carried out a quantitative LEED-IV study in the energy range between 50 and 180 eV. We investigated the adsorption geometry of the Sr(1 × 5) structure on Mo(211) including the relaxations in the substrate. These results are compared with those obtained recently for the Li(1 × 4) structure on the same surface. The long-range indirect interactions between both types of adsorbate atoms that are responsible for ordering of the chains in the [01̄1] direction are correlated with substantial lateral substrate relaxations by up to 0.2 angstrom along the Mo(211) [1̄11] furrow direction. For both adsorbates, the relaxations form wave-like density modulations in the substrate that seem to be caused by Friedel oscillations of the substrate conduction electrons. These screen the local adsorbate-induced distortion of the electron density. The variation of periodicity and the corresponding change of effective screening length between the two adsorbates may be due to surface states involved in the bond formation. Whereas for Sr, the Langmuir-Gurney (LG) model still provides a consistent picture of bond formation compared with the observed bond lengths and changes of work function, the predictions of the LG model are inconsistent with the experimental findings for Li.
UR - http://www.scopus.com/inward/record.url?scp=0342572503&partnerID=8YFLogxK
U2 - 10.1016/S0039-6028(00)00432-5
DO - 10.1016/S0039-6028(00)00432-5
M3 - Article
AN - SCOPUS:0342572503
VL - 459
SP - 265
EP - 276
JO - Surface Science
JF - Surface Science
SN - 0039-6028
IS - 3
ER -