Geometrical significance of the orientation of defect-induced electric field gradients

One of the features of defect-induced axial symmetric electric field gradients(efg) is the orientation of their symmetry axis with respect to the crystal lattice. Especially in the case of simple trapped defects(mono-, di-vacancies, single interstitials or single impurity atoms) this orientation should follow the symmetry of the geometrical probe atom defect arrangement. This will be illustrated by PAC measurements at¹¹¹In/¹¹¹Cd for the case of trapped impurity atoms in Cu.This work was supported by the Bundesminister für Forschung und Technologie.