Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 10: Computational Materials Modelling II - Theory/Numerics

MM 10.4: Vortrag

Montag, 31. März 2014, 12:30–12:45, IFW D

Analytic Bond-Order Potential for Fe and Fe-C — •Sebastian Schreiber, Thomas Hammerschmidt, and Ralf Drautz — Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum

The analytic bond-order potential (BOP) is an interatomic potential, that provides a linear scaling solution to the tight-binding (TB) energy. It includes itinerant magnetism and charge transfer explicitly and may be viewed as a systematic extension of second-moment models (e.g. Finnis-Sinclair) to include higher moment contributions. In the analytic BOPs the bond-order, the density of states, the atomic magnetic moments and charges adjust self-consistently according to the atomic environment. The analytic BOP also provides exact derivatives of the energy for calculating forces and stress.

Here, we demonstrate the transferability of recently developed TB models for Fe and Fe-C to the analytic BOP formalism. We present BOP simulations for core structures and Peierls barriers of a/2[111]-screw-dislocations in α-Fe. We also discuss the interaction of these line-defects with carbon impurity atoms and its impact on plastic deformation.