Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 45: Electronic structure I
O 45.9: Vortrag
Mittwoch, 24. März 2010, 12:30–12:45, H33
Structure and Energetics of Si(111)5×2−Au Atomic Chains — •Ingo Barke1, Steven C. Erwin2, and F. J. Himpsel3 — 1Universität Rostock, Germany — 2Naval Research Laboratory, Washington, DC — 3University of Wisconsin-Madison, WI
We propose a structural model for the Si(111)5x2-Au reconstruction [1]. The model incorporates a revised experimental value of 0.6 monolayer for the coverage of gold atoms, equivalent to six gold atoms per 5 × 2 cell [2]. Results obtained from first-principles total-energy calculations are in excellent agreement with experimental observations: (1) In the presence of silicon adatoms the periodicity of the gold rows spontaneously doubles. (2) The dependence of the surface energy on the adatom coverage indicates that a uniformly covered phase is unstable and will phase separate into empty and covered regions. (3) High-resolution scanning tunneling microscopy images are precisely reproduced by theory. (4) The calculated band structure is consistent with angle-resolved photoemission spectra. (5) The calculated activation barrier for diffusion of silicon adatoms along the row direction is in excellent agreement with the experimentally measured barrier [3].
[1] S. C. Erwin et al., Phys. Rev. B 80, 155409 (2009)
[2] I. Barke et al., Phys. Rev. B 79, 155301 (2009)
[3] E. Bussmann et al., Phys. Rev. Lett. 101, 266101 (2008)