Free enthalpy of ternary alloy superlattice

Increments due to superlattice structure are formulated for the free enthalpy and some other thermodynamic entities as functions of composition, geometry parameters and temperature. Physical contents of the general expressions, derived for simple (quasi-regular) pseudobinary solutions, are illustrated by numerical data valid for the In/sub x/Ga/sub 1-x/As/GaAs system. It is suggested that the free enthalpy of superlattice, is, at least at higher temperatures, largely dominated by the configuration entropy term. Corrections due to nonideality appear to be quite sizeable for the selected ternary alloy. (author)