J. Phys. Soc. Jpn. 77, 123706 (2008) [4 Pages]
LETTERS

The Energetics of Hut-Cluster Self-Assembly in Ge/Si(001) from Linear-Scaling DFT Calculations

+ Affiliations
1National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-00472Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, U.K.3Materials Simulation Laboratory, University College London, Gower Street, London WC1E 6BT, U.K.4London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, U.K.

Density functional theory (DFT) in a linear-scaling implementation is used to study the energetics of three-dimensional (3D) Ge islands (hut clusters) grown on Si(001) surface. DFT calculations on the fully relaxed energies of a series of hut clusters of increasing size are reported, finding a 2D to 3D cross-over near three monolayers; the number of atoms in the largest simulated system is over 20,000. A variety of technical issues which are important in addressing the accuracy and validity of the calculations are described and assessed. The results suggest that energetics alone is responsible for the initial transition from 2D to 3D growth.

©2008 The Physical Society of Japan

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