First-Principles Interatomic Potentials in Transition Metals: Multi-Ion Interactions and Their Analytic Representation.

摘要

The first-principles, density-functional version of the generalized pseudopotential theory, previously developed for empty- and filled-d-band metals, has now been extended to pure transition metals with partially-filled d bands. Within this formalism, a rigorous real-space expansion of the bulk total energy has been obtained in terms of widely transferable, structure-independent interatomic potentials, including both central-force pair interactions and angular-force triplet and quadruplet interactions. In the central transition metals, the three-ion and four-ion potentials are essential to a proper description of materials properties, but are necessarily multi-dimensional functions which cannot be easily tabulated. We have, therefore, also developed a simplified version of the theory in which these potentials can be expressed analytically while retaining the most important physics of the full first-principles treatment. The analytic potentials are suitable for wide-scaled applications, including molecular-dynamics and Monte-Carlo simulation. The first-principles and analytic theories are here reviewed together with selected applications to the prediction of high-pressure structural phase transitions; phonon anomalies and their close correlation with the present multi-ion potentials; and the vacancy-formation energy. 26 refs., 4 figs., 1 tab.