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Abstract

A fundamental understanding of the macroscopic behaviour of materials requires insight into the mechanisms of bond-breaking and bond-making during atomic rearrangements. Our goal is to capture both, the atomistic detail and the characteristic length-scale of the underlying mechanisms, by large-scale atomistic simulations. A key requirement for insightful simulations is a reliable, transferable, and computationally efficient description of the interatomic interactions.

To this end, we develop analytic bond-order potentials (BOPs) that are derived by systematically coarse-graining the electronic structure from physically and chemically intuitive tight-binding (TB) bond models to the analytic BOPs through a moments expansion of the local density of states. The analytic BOPs depend explicitly on the valence of the elements and account for charge transfer and magnetic contributions to the binding energy. They provide a similar accuracy as TB calculations at less computational effort and thus allow for large-scale atomistic simulations of systems which cannot be described by classical empirical potentials. This talk gives an overview of the development and implementation of analytic BOPs in the context of steels, refractory metals and intermetallics.