Supercell Calculations of Positron Trapping and Annihilation at Vacancies in Simple and Transition Metals

摘要

A new approach, based upon augmented-plane-wave calculations in a supercell lattice, was developed to theoretically predict the annihilation characteristics of the positron in vacancies, taking into account for the first time the atomic nature of the solid. This method, which is general and suited equally well to both simple and transition metals, was used to calculate positron trapping and annihilation characteristics in Al, Nb, Ta, and W. The results indicate that the positron is sufficiently strongly trapped in a vacancy in all of these metals that significant thermal detrapping in any of them is highly unlikely. 13 references. (ERA citation 04:045531)