Publications
Comparison of analytic and numerical bond-order potentials for W and Mo
M. Čák, T. Hammerschmidt, R. Drautz.
Journal of Physics: Condensed Matter, 25, 265002, (2013)
Abstract
Bond-order potentials (BOPs) are derived from the tight-binding approximation and provide a
linearly-scaling computation of the energy and forces for a system of interacting atoms. While
the numerical BOPs involve the numerical integration of the response (Green’s) function, the
expressions for the energy and interatomic forces are analytical within the formalism of the
analytic BOPs. In this paper we present a detailed comparison of numerical and analytic
BOPs. We use established parametrizations for the bcc refractory metals W and Mo and test
structural energy differences; tetragonal, trigonal, hexagonal and orthorhombic deformation
paths; formation energies of point defects as well as phonon dispersion relations. We find that
the numerical and analytic BOPs generally are in very good agreement for the calculation of
energies. Different from the numerical BOPs, the forces in the analytic BOPs correspond
exactly to the negative gradients of the energy. This makes it possible to use the analytic BOPs
in dynamical simulations and leads to improved predictions of defect energies and phonons as
compared to the numerical BOPs.
DOI: 10.1088/0953-8984/25/26/265002
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