Vacancy formation in indium investigated by positron lifetime spectroscopy

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Abstract
A detailed analysis of positron lifetime spectra measured for In between 77 and 420K with high time resolution clearly shows the validity of the simple two-state trapping model. With the rate sigma 1V of positron trapping per unit vacancy concentration assumed to be independent of temperature the vacancy formation enthalpy HIVF=0.54+or-0.03 eV is determined from the parameters deduced from the lifetime spectra. The influence of a temperature dependence of sigma IV suggested by theoretical considerations is discussed. A comparison with earlier self-diffusion data yields the vacancy migration enthalpy HIVM=0.27+or-0.04 eV, which is discussed together with results of non-equilibrium experiments.