ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Comparison of analytic and numerical bond-order potentials

Date: 13.03.2013
Place: DPG Spring Meeting 2013, Regensburg, Germany

Miroslav Čák

A systematic coarse-graining of the electronic structure leads from DFT to tight-binding and to bond-order potentials (BOP). The calculation of the total energy of a system of interacting atoms can be carried out within the formalism of either analytic or numerical BOP. Recently, we developed parameterizations of analytic BOPs for the refractory metals Tungsten, Molybdenum, Niobium and Tantalum. These refractory metals play an important role as strengtheners of nickel- and cobalt-based superalloys. Here we employ these parameterizations for a detailed comparison of numerical and analytic BOP. In particular, we investigate structural energy differences for different competing structures; tetragonal, trigonal, hexagonal and orthorhombic deformation paths; formation energies of point defects and phonon dispersion relations. We find a very good agreement between analytic and numerical BOP in all tests. Furthemore, comparing our BOP calculations to corresponding first-principles, tight-binding and experimental results shows a very good transferability of both BOP schemes to atomic structures encountered in lattice defects.

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