Configuration entropy of ternary alloy superlattice

Difference in mixture‐related entropy between superlattice and the corresponding homogeneous crystal in which all composition gradients have been annihilated by equilibrating processes (the configuration entropy of superlattice, Δ S conf ) is analytically formulated as a function of composition variables and geometry parameters. Numerical evaluations are performed for the important case of Al x Ga 1− x As‐based superlattice. Qualitative trends confirm in general the intuitive expectations (− Δ S conf grows with increasing composition difference between the layers); the dependencies on geometry parameters exhibit a peculiar behaviour. The results are applicable to superlattices with periode lengths sufficiently in excess of the monoatomic layer thickness.