METAL-INSULATOR-TRANSITION IN THE AUBRY MODEL OF ONE-DIMENSIONAL INCOMMENSURATE SYSTEMS

Numerical methods are used to investigate the metal-insulator transition in the Aubry model of one-dimensional incommensurate systems. Our numerical results seem to indicate that a range of intermediate states exists between extended and localized states. However, there are no exact boundary lines between the extended and the intermediate states, or between the intermediate and the localized states, because some of the intermediate states resemble extended ones and some others resemble weakly localized states. There is a gradual transition from extended to localized states in a zone including V = 2t, but not only at V = 2t, and therefore our conclusion is different from that of the duality theory.