Two Dimensional Angular Correlation of Positron Annihilation in Al and Cu Single Crystals Containing Edge Dislocations

The electronic structure around edge dislocations in Al and Cu single crystals was studied by the two dimensional angular correlation measurements of positron annihilation radiations(2D-ACAR). The momentum distribution aroud edge dislocations was found to be isotropic. A complete disappearance of crystal symmetry effects on Fermi surfaces such as the monster in Al and the <111> neck in Cu was clearly observed.