Computational Study of Positron–Monovacancy Interaction ind-Block Metals

The positron–monovacancy interaction in d-block metals (except for Mn, Tc, and Hg) has been studied by the two-component density-functional-theory formalism [E. Boroński and R. M. Nieminen, Phys. Rev. B 34, 3820 (1986)]. On the unrelaxed structure, the positron lifetime calculated with the presence of a positron is generally longer than that obtained neglecting the positron effect. When the atomic positions are relaxed, the difference is widened, especially for the group V metals. The inward relaxation of the atoms surrounding the monovacancy is suppressed when the positron effect is taken into account. The difference in the positron lifetime can be also related to the bulk modulus and the cohesive energy.