Vacancy formation energy of metals determined by using positron age-momentum correlation technique

The vacancy formation energy E-v of Zn and In are determined by using the positron age-momentum correlation (AMOC) technique. The S-parameter S-v for the trapped positrons that is necessary for the analysis is obtained by extrapolating the time dependent S-parameter S(t). Thus it is not necessary to heat up the sample so high that all positrons arc trapped in vacancies. The E-v of Zn thus obtained was in good agreement with the reported value. Also we obtained the E-v of In, for which the previously reported values are scattered over a considerable range.