Monovacancy Formation Energies in Cubic Crystals

Using the conception of an extended object (Umezawa et al.) based on the continuum theory of elasticity, monovacancy formation energies are calculated. Anisotropy is included for cubic symmetry by means of a first order approximation to the Green's function tensor and some tensor algebraic calculations. The last considerations contribute to a better understanding of the meaning of “Voigt's average isotropic elastic constants”. Further lattice structure effects are taken into account by a common parameter for every type of structure. A comparison with experimental data or results from other theories shows either satisfactory agreement or the inconsistency of the first order approximation to the anisotropy for some materials with common properties.