The electron and positron charge densities are calculated as a function of
position in the unit cell for the Hg1-xCdxTe alloy system using the empiric
al pseudopotential method combined with the virtual-crystal approximation.
The results show that the positron has a strong affinity to one sort of ato
ms in binary semiconductors. The results of the positron charge density sho
uld provide valuable insight into the effect of annihilation. The electron
charge density and the ionicity character with respect to the variation of
the mole fraction are discussed.