Trends in the thermal expansion coefficients of the AIBIIIC2VIand AIIBIVC2Vchalcopyrite compounds

Empirical relations are derived for the average linear thermal expansion coefficient αLand the linear thermal expansion coefficients αaand αcof the lattice parametersaandc, respectively, of the AIBIIIC2IVand AIIBIVC2Vcompounds. It is shown that the thermal expansion coefficients of all tetrahedrally coordinated compounds can be described within the same model. The anisotropy of the thermal expansion coefficients depends essentially on the lattice constant ratioc/a. There exists a criticalc/avalue below of which αcbecomes negative.