Theory of the Phase Transition in Iv-vi Compounds
نویسنده
چکیده
The thermodynamic theory of second order phase transitions in crystals with the modifications and simplifications recently made by the author and co-workers is applied to the rocksalt structure. We predict several lower symmetry phases achievable via second-order displacive transitions which do not change the unit cell, in addition to the trigonal structure seen in GeTe. A microscopic model is proposed for such transitions, involving space-group configurational (Jahn-Teller) instability of a proposed valence-bond model of electronic structure of binding of these compounds. Some experimentally verifiable tests of these proposals are given.
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