Positron annihilation studies in Ga_xIn_1-xAs

The effect of alloying on the electron-positron momentum densities, ρ{variant}(p), in Ga_xIn_1-xAs is reported. Our computations of ρ{variant}(p) are based on the independent particle approximation (IPM) coupled with the empirical pseudopotential method (EPM). To make allowance for the chemical disorder, the virtual crystal approximation is used, including a correction to the alloy potential. An illustrative result of the electron-positron momentum densities show a deviation from linearity at low momentum which indicates the alloying effect (bowing effect).