State-of-the-art ab initio calculations were made of the point defect structure (vacancy and self-interstitial atoms) in hexagonal Zr. Contrary to previous results, obtained using empirical potentials, it was found that the octahedral configuration should be the most stable for self-interstitial atoms, immediately followed by the basal octahedral and basal crowdion; all 3 structures having very similar formation energies.

Ab initio Atomic-Scale Determination of Point-Defect Structure in HCP Zirconium. C.Domain, A.Legris: Philosophical Magazine, 2005, 85[4-7], 569-75