Views from the Electronic Structure of (GaAs) n (AlAs) n Short Period Superlattices

Very short period superlattices including strained superlattices have recently aroused keen interests as a new class of materials among semiconductor superlattices and have been extensively studied both theoretically and experimentally. In particular, very short period GaAs/AlAs superlattices with (001) interface was one of the highlight topics among various kinds of superlattices for recent several years. A number of first principles band structure and stability calculations have been performed for (GaAs) n (AlAs) n superlattices with (001) interface, and a number of experimental groups have tested theoretical results. This plenary lecture is devoted to give an overview on the recent remarkable progress in research on the band structures and optical properties of this system. Finally, as a direction in the future prospect of research on this system, the improvement of the band gap problem in the local density approximation and the sample problem is discussed.