The excess energy of several III-V and II-VI strained-layer semiconductor superlattices (AC${)}_p$(BC${)}_p$ is studied as a function of the repeat period p and orientation G=[001], [110], [111], and [201], using first-principles calculations. We discover a number of universal features, including the predicted instability for nearly all p’s and G’s with respect to bulk disproportionation, the identification of chalcopyrite as a metastable ordered structure, and the stability of all thin epitaxial [110] and [201] and most common-anion [001] superlattices relative to coherent phase separation.

• Received 11 September 1989

DOI:https://doi.org/10.1103/PhysRevLett.64.36