Analytic bond-order potentials for the bcc refractory metals Nb, Ta, Mo and W

Area of Science:

• Materials Science
• Computational Materials Science
• Condensed Matter Physics

Background:

• Bond-order potentials (BOPs) are derived from the tight-binding approximation.
• Analytic BOPs offer an efficient method for calculating atomic system energies and forces.

Purpose of the Study:

• To present parametrizations of analytic BOPs for bcc refractory metals: Niobium (Nb), Tantalum (Ta), Molybdenum (Mo), and Tungsten (W).
• To validate the developed parametrizations by testing them against various non-equilibrium atomic configurations.

Main Methods:

• Development and optimization of analytic bond-order potentials (BOPs).
• Testing against structural energy differences for various crystal structures.
• Evaluation of deformation paths (tetragonal, trigonal, hexagonal, orthorhombic).
• Calculation of point defect formation energies and phonon dispersion relations.

Main Results:

• Parametrizations show good agreement with existing experimental and theoretical data.
• Accurate prediction of energetic ordering for vacancy and self-interstitial atom configurations.
• Validation across diverse, far-from-equilibrium atomic environments.

Conclusions:

• The developed analytic BOPs provide a reliable tool for simulating refractory metals.
• The potentials accurately capture complex material behaviors beyond equilibrium conditions.
• Results align with density functional theory calculations for defect energetics.