Comment on ‘‘Effective-mass superlattice’’

In a paper by Sasaki [Phys. Rev. B 30, 7016 (1984)], a new type of effective-mass superlattice (EMSL) was proposed and candidate materials for it were given. A band-structure determination for zero transverse wave vector $k_t$ was presented as well. It was shown in our previously published papers that the flat potential (present in EMSL) is actually a special case that holds for singular $k_t$ values (e.g., $k_t$=0), the potential varying periodically for all other $k_t$ values. This fact influences the EMSL band structure and other parameters in a nontrivial way.