Abstract
Ge deposited on Si(100) initially forms heteroepitaxial layers, which grow to a critical thickness of ∼3 MLs before the appearance of three-dimensional strain relieving structures. Experimental observations reveal that the surface structure of this Ge wetting layer is a dimer vacancy line (DVL) superstructure of the unstrained Ge(100) dimer reconstruction. In the following, the results of first-principles calculations of the thickness dependence of the wetting layer surface excess energy for the c(4 × 2) and 4 × 6 DVL surface reconstructions are reported. These results predict a wetting layer critical thickness of ∼3 MLs, which is largely unaffected by the presence of dimer vacancy lines. The 4 × 6 DVL reconstruction is found to be thermodynamically stable with respect to the c(4 × 2) structure for wetting layers at least 2 ML thick. A strong correlation between the fraction of total surface induced deformation present in the substrate and the thickness dependence of wetting layer surface energy is also shown.
Original language | English |
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Article number | 205337 |
Pages (from-to) | 205337-1-205337-7 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 70 |
Issue number | 20 |
DOIs | |
State | Published - Nov 2004 |
Bibliographical note
Funding Information:This work was supported by the National Science Foundation under Program No. DMR-0102794, and made use of computing resources provided by NPACI at the University of Michigan. The authors also thank P. W. Voorhees for helpful discussions.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics