POSITRON-ANNIHILATION IN NARROW-GAP SEMICONDUCTORS

The valence electron and positron charge densities in InAs and InSb ar e obtained from wave functions derived in a model pseudopotential band -structure calculation. It is found that the positron density is maxim um in the open interstices and is excluded not only, as usual, from th e ion cores but also to a considerable degree from the valence bonds. Electron-positron momentum densities are calculated for the (001-110) plane. The results are used to analyze the positron effect in narrow-g ap semiconductors.