Effects of stoichiometries on the positron distribution in Si1-x-yGexCy alloys

The effect of alloying on the positron distribution in Si1–x–yGexCy alloys is reported. Our computations of the thermalized positron densities are based on the independent particle method coupled with the empirical pseudopotential method to derive the positron and electron wave functions, respectively. Initial results show a clear symmetrical positron charge distribution relative to the bond centre, a quite similar situation that was found in the IV groups. Since the minimum band gaps were found to be very sensitive to the carbon as well as the germanium concentration variations, this has an immediate consequence on the positron densities, where we find a deviation from linearity. This illustrative result was an indication of the alloying effect in this system (bowing effect).