Effect of crystal potential on electric field gradient calculations due to impurities in cubic metals
The electric field gradients caused by interstitial and substitutional point defects in f.c.c. metals have been studied. The perturbation on the host electron distribution has been calculated self-consistently using density functional formalism. The effect of strain caused by size difference between host and impurity atoms is treated in the point-ion model. The influence of the host potential on impurity perturbation is incorporated within the spherical solid approximation. The theory is applied to positive muon and mono-vacancy in Al and Cu hosts. The theoretical results are in good agreement with experiment and illustrate the importance of both strain and conduction electron contribution to the electric field gradient.