Hamburg 2001 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Oberflächenphysik
O 13: Postersitzung (Adsorption auf Oberfl
ächen, Oberfl
ächenreaktionen, Elektronische Struktur, Epitaxie und Wachstum, Halbleiteroberfl
ächen und Grenzfl
ächen, Oxide und Isolatoren)
O 13.73: Poster
Montag, 26. März 2001, 19:00–22:00, Foyer zu B
A novel reconstruction of the GaAs(001) surface under conditions of low As pressure — •Sung-Hoon Lee1, W. Moritz2, and M. Scheffler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14159 Berlin — 2Institut für Kristallographie und Angewandte Mineralogie, Universität München, Theresienstr. 41, 80333 München
The c(8x2) reconstruction of GaAs(100) has been identified using density functional theory, simulated STM images and LEED. The structure differs from the usually assumed surface dimer based reconstructions of the III/V semiconductor surfaces and shows two subsurface Ga-dimers in the second layer which are covered by a nearly planar atomic layer consisting of sp2 bonded Ga-atoms and sp3 bonded As atoms together with a Ga-dimer. The structure is energetically more favorable than all previously proposed models at low As pressures. The DFT calculations were performed for models with (4x2) periodicity as the c(8x2) structure is built from (4x2) units. The simulated STM-images using the Tersoff-Hamann approach were in good agreement with high resolution STM images of Xue et al. [1] and Skala et al.[2]. The model is further supported by a LEED I/V analysis using previously published experimental data from Cerdá et al. [3].
[1] Q.K. Xue et al., Phys. Rev. Letters 74, 3177 (1995).
[2] S.L. Skala et al., Phys. Rev. B 48, 9138 (1993).
[3] J. Cerdá, F. Palomares, and F. Soria, Phys.Rev.Lett.75, 665 (1996).