Correlation between positron affinity and ionicity in semiconductors

The independent particle method (IPM) coupled with empirical pseudopotential method (EPM) was used to compute the thermalized positron charge densities in specific family of binary tetrahedrally coordinated crystals of formula ANB8−N. Initial results show a clear asymmetrical positron charge distribution relative to the bond center. This positron affinity lead us to establish an empirical formula for the calculation of the ionicity character in these semiconductors. A good agreement was found between our calculations and the Phillips ionicity scale.