Density Functional Theory Calculation of Properties of Point Defects in δ-Plutonium

Abstract

Local density approximation (LDA) +U within the framework of density functional theory (DFT) was used to study the properties of vacancy and self-interstitial atom (SIA) in δ-Pu. The results show that mono-vacancy, di-vacancy and tri-vacancy existing in δ-Pu shift rightward the f shell peak of the projected density of states (PDOS), the peak values of mono-vacancy and di-vacancy decrease, while the peak value of tri-vacancy increases. The saddle point during vacancy migration shifts leftward the f shell peak of PDOS, and the peak value decreases. The octahedral SIA, the tetrahedral SIA, the split SIA shift leftward the f shell peak of PDOS, and the peak values decreases. Finally, the recombination behavior of vacancy and SIA were studied at both the spin-restricted and the spin-unrestricted level, SIA migrates to vacancy site, and exhibits a tendency to forming the perfect fcc structure.