The Electronic Structure and Transmission Characteristics of Disordered AlGaAs Nanowires

Perfect nanowires may be studied from both the bandstructure and transmission perspectives, and relating features in one set of curves to those in another often yields much insight into their behavior. For random-alloy nanowires, however, only transmission characteristics and virtual-crystal approximation (VCA) bands have been available. This is a serious shortcoming since the VCA cannot properly capture disorder at the primitive cell level: those bulk properties which it can satisfactorily reproduce arise from spatially extended states and measurements which average out primitive cell-level fluctuations. Here we address this deficiency by projecting approximate bands out of supercell states for Al_0.15Ga_0.85As random alloy nanowires. The resulting bands correspond to the transmission characteristics very closely, unlike the VCA bands, which cannot explain important transmission features. Using both bandstructure and transmission results, we are better able to explain the operation of these nanowires