Theoretical calculation of positron trapping by embedded nanoclusters

Abstract

The trapping and annihilation characteristics of positrons in nanosized solute atom clusters (Mg, Ag, Au) embedded in Al crystals were studied by theoretical calculations based on the atomic superposition model (ATSUP). The results confirm the effective confinement of the positron wavefunction inside clusters with a diameter less than 1 nm, which contain only a few atoms. With increasing nanocluster size, the trapping of positrons is gradually enhanced leading to an increased positron annihilation lifetime. Our results suggest that positron lifetime spectroscopy should be a sensitive probe for Ag, Au, and Mg nanoclusters in Al matrix.