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MM: Fachverband Metall- und Materialphysik

MM 3: Computational Materials Modelling I

MM 3.1: Vortrag

Montag, 14. März 2011, 11:00–11:15, IFW B

Properties of positrons at defects in metal — •Martin Offenberger¹, Hubert Ebert¹, and John Banhart² — ¹Ludwig-Maximilians-Universität München — ²Helmholtz Zentrum Berlin

Positron annihilation is a well established tool to study defects in metals in experiment. To simulate positron annihilation experiments, an accurate and efficient description of both positrons and defects is needed. To calculate clusters of impurity atoms in a metal host, we use the Korringa-Kohn-Rostoker Green’s function method (KKR-GF). This approach deals with the defect region by means of the Dyson equation instead of a supercell approach, avoiding artificial boundary conditions. Positrons are then calculated according to the conventional scheme suggested e.g. by Boroński and Nieminen. Results of our calculations presented include positron charge distributions, density of states and annihilation lifetimes for a variety of defects in Aluminium. In addition, the properties of defects like vacancies and transition metal impurity-vacancy dimers as positron traps will be discussed.