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Reduced tight-binding models for elemental Si and N, and ordered binary Si-N systems

: Gehrmann, J.; Pettifor, D.G.; Kolmogorov, A.N.; Reese, M.; Mrovec, M.; Elsässer, C.; Drautz, R.

Postprint urn:nbn:de:0011-n-3365948 (566 KByte PDF)
MD5 Fingerprint: 9f02dc220d80b717b0e471a7c6252d63
Created on: 27.9.2016

Physical Review. B 91 (2015), No.5, Art. 054109
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
Deutsche Forschungsgemeinschaft DFG
MR 22/5-1,2
Journal Article, Electronic Publication
Fraunhofer IWM ()
tight binding; silicon nitrate; total energy

Silicon nitride is a bulk and a coating material exhibiting excellent mechanical properties. We present a transferable reduced tight-binding (TB) model for the silicon nitride system, developed within the framework of coarse graining the electronic structure from density-functional theory (DFT) to tight binding (TB) to bond-order potentials (BOPs). The TB bond integrals are obtained directly from mixed-basis DFT projections of wave functions onto a minimal basis of atom-centered orbitals. This approach reduces the number of overall parameters to be fitted. Furthermore, applying the reduced TB approximation automatically leads to a single sigma bond order that contributes to the bond energy. DFT binding energies of ground state and metastable crystal structures are used as the benchmark to which the TB repulsive parameters are fitted. The quality of the TB models is demonstrated by comparing their predictions for the binding energies, heats of formation, elastic constants, and defect energies with DFT and experimental values.