POSITRON-ANNIHILATION STUDIES IN GAXIN1-XAS

The effect of alloying on the electron-positron momentum densities, rh o(p), in GaxIn1-xAs is reported. Our computations of rho(p) are based on the independent particle approximation (IPM) coupled with the empir ical pseudopotential method (EPM). To make allowance for the chemical disorder, the virtual crystal approximation is used, including a corre ction to the alloy potential. An illustrative result of the electron-p ositron momentum densities show a deviation from linearity at low mome ntum which indicates the alloying effect (bowing effect).