Full-potential KKR calculations for point defect energies in metals, based on the generalized-gradient approximation: I. Vacancy formation energies in fcc and bcc metals

We present systematic first-principle, calculations for vacancy formation energies E-V(F) in most of elemental metals (Li Au) of fee and bee structures, as well as bulk propertied such as lattice parameters a and bulk moduli B The calculation, are based on the generalized-gradient approximation in density-functional formalism. proposed by Perdew and Wang in 1991 (PW91-GGA), and apple the Korringa-Kohn-Rostoker Green's function method for perfect crystals and point defect systems. developed by the Julich group. First we show that the calculated bulk properties for all elements studied are in excellent agreement with the experimental results the PW91-GGA corrects the deficiencies of the local spin density approximation for metals. i.e., the underestimation of a and the overestimation of B and the theoretical errors in a and B are reduced within similar to 1% and similar to 10% of experimental results respectively. Second we show that E-V(F) for most of fcc metals are reproduced within the experimental errors. while E-V(F) for most of bee metals are overestimated by 10% 20% of the experimental results. It is noted that the comparison with the experimental result, needs the inclusion of the thermal lattice expansion effect if the first-principles calculations because most of the experimental results were derived from positron annihilation measurement high temperatures. The remaining discrepancies between theory and experiment are also discussed.