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K. Scheerschmidt and V. Kuhlmann
Molecular dynamics simulations using empirical potentials have been performed to describe atomic interactions during the relaxation of nanostructures. To include the quantum mechanical nature of atomic bonding a tight-binding based bond order potential is developed applying analytically the most important momenta up to 6th order. The applicability of the bond order potential and resulting enhancements in structural predictions are analyzed recalculating quantum dot relaxations.
The Figures show a free-standing SiGe quantum dot deposited on a Si (100) surfaces relaxed with the Tersoff potential (left Figure) and the BOP4+ potential (right Figure). During the annealing cycle OK - 900K - 0K an increased stability is obtained due to the higher stiffness in BOP4+.