Positron affinity in Zn1-xCdxSe

The independent particle model (IPM) coupled with the use of the virtual cr ystal approximation (VCA) which incorporates compositional disorder as an e ffective potential was used to compute the positron charge distribution in the cubic structured ternary alloy Zn1-xCdxSe. The positron charge density with respect to the variation of the mole fraction is discussed. The result s show that positrons have a strong affinity fur the anion than fur the cat ion. This relative positron affinity should lead to the positron preferenti ally annihilating with the anion rather than the cation. (C) 2000 Elsevier Science Ltd. All rights reserved.