Improved nonorthogonal tight-binding Hamiltonian for molecular-dynamics simulations of silicon clusters
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)
- Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)
We present an improvement over the nonorthogonal tight-binding molecular-dynamics scheme recently proposed by Menon and Subbaswamy [Phys. Rev. B 47, 12 754 (1993)]. The proper treatment of the nonorthogonality and its effect on the Hamiltonian matrix elements has been found to obviate the need for a bond-counting term, leaving only two adjustable parameters in the formalism. With the improved parametrization we obtain values of the energies and bonding distances which are in better agreement with the available [ital ab] [ital initio] results for clusters of size up to [ital N]=10. Additionally, we have identified a lowest energy structure for the Si[sub 9] cluster, which to our knowledge has not been considered to date. We show that this structure (a distorted tricapped trigonal prism with [ital C][sub 2[ital v]] symmetry) is also a minimum at the Hartree-Fock level and in approximate density-functional theory, and should therefore be seriously considered as a candidate for the ground-state structure of the Si[sub 9] cluster.
- DOE Contract Number:
- FC22-93PC93053
- OSTI ID:
- 7247298
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 50:8; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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