| AVS 54th International Symposium | |
| Surface Science | Monday Sessions |
| Session SS2-MoM |
| Session: | Surface Structure, Growth, and Etching of Silicon and Germanium |
| Presenter: | P.C. Snijders, Delft University of Technology, The Netherlands (now at ORNL) |
| Authors: | P.C. Snijders, Delft University of Technology, The Netherlands (now at ORNL) E.J. Moon, University of Tennessee, Knoxville C. Gonzalez, Universidad Autonoma, Madrid, Spain J. Ortega, Universidad Autonoma, Madrid, Spain F. Flores, Universidad Autonoma, Madrid, Spain H.H. Weitering, University of Tennessee, Knoxville, and Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Ga adsorption on the Si(112) surface results in the formation of pseudomorphic Ga atom chains. Compressive strain in these atom chains is relieved via creation of adatom vacancies.1 These vacancies selforganize into meandering vacancy lines (VLs) similar to the well-known nx2 superstructures for Ge on Si(100).2 We show that the average spacing between these line defects can be experimentally controlled continuously, within limits, by adjusting the chemical potential µ of the Ga adatoms. The small VL spacings in this system result in significant VL correlations that cannot be captured within a mean field analysis of the VLs.2 We derive a conceptually new lattice model that quantitatively connects Density Functional Theory (DFT) calculations for perfectly ordered structures, with the fluctuating disorder seen in experiment and the experimental control parameter µ for this correlated VL system. Applying this model to statistical data from large scale STM images, we calculate the (repulsive) VL interaction energy and the kink energy. This hybrid approach of lattice modeling and DFT can be applied to other examples of line defects in hetero-epitaxy, especially in cases where correlation effects are significant and a mean field approach is not valid.3
1 C. Gonzalez, P.C. Snijders, J. Ortega, R. Perez, F. Flores, S. Rogge, and H.H. Weitering, Phys. Rev. Lett. 96, 126106 (2004), P.C. Snijders, S. Rogge, C. Gonzalez, R. Perez, J. Ortega, F. Flores, and H.H. Weitering, Phys. Rev. B 72, 125343 (2005).
2 X. Chen, F. Wu, Z. Zhang, and M.G. Lagally, Phys. Rev. Lett. 73, 850 (1994).
3 Part of this work (HHW) was supported by the US DOE Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, through Oak Ridge National Laboratory which is managed by UT-Battelle, LLC.