Unstable equilibrium and radiation defects in solids

A new type of point defect in solids genetically related with Frenkel's pairs which appears when there exists the instability zone of pair vacancy (v) - interstitial atom (i). It is shown that, at large instability zones typical of ‘loose’ crystalline structures, equilibrium concentration of unstable pairs i-v may exceed the concentration of usual Frenkel's pairs. In the example of the semiconducting crystals In₂Te₃ and Ga₂Te₃ having loose structure it is experimentally demonstrated that equilibrium point defects cannot be preserved by specimen quenching and that irradiation by large doses of high-energy particles does not result in stable radiation defects formation.