PHONON-DISPERSION CURVES FOR TRANSITION-METALS WITHIN THE EMBEDDED-ATOM AND EMBEDDED-DEFECT METHODS

Phonons in bce Mo, Fe, and Cr have been calculated using embedded-atom -method (EAM)-type and embedded-defect (ED) potentials. The latter is an extension of the EAM that introduces angular interactions through a many-body approach. In contrast with the EAM formalism, the ED calcul ated elastic constants can be fitted to the experimental values even i n those metals with a negative Cauchy pressure. The contributions of t he pair and many-body interaction terms to the phonon frequencies are studied. It is found that the EAM and ED interatomic potentials show s ome limitations to reproduce the experimental dispersion curves for bc c and fee structures; such limitations an analyzed.