A New Interatomic Potential for Non-Metals
Many applications of atomistic computer modelling require clusters of order a thousand atoms or more. Dislocations and cracks are good examples, and in their cases an accurate description of the highly defective core region is not possible without comparable accuracy in the surrounding elastic region (which may also be faulted). At this scale of simulation, ab initio calculations themselves are not feasible. Recently there have been several attempts to store the results of ab initio calculations on small molecules or supercells in the form of a classical interatomic potential (for example, the potentials due to Tersoff1 and Biswas/Hamann2). Both initial attempts by these authors foundered on several structures. They have since been modified3,4, but unfortunately in the case of Tersoff’s potential without removing all the shortcomings5. For modelling line defects in diamond and graphite structures we have developed a potential in the spirit of Tersoff’s potential, in which a geometrical construction is invoked for more bond information and elastic anisotropy and stacking fault energies are introduced.
KeywordsStack Fault Energy Graphite Structure Diamond Structure Equilibrium Bond Length Electronic Kinetic Energy
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