LOCAL CORRELATIONS IN ONE-DIMENSIONAL AND 2-DIMENSIONAL DISORDERED-SYSTEMS

In one-dimensional disordered systems all states are localized but when you add local correlations, such as a dimer impurity, some states become delocalized. In this paper, a wide range of correlations are studied leading to a delocalization of states. Moreover, second-nearest-neighbour models which also have extended states are investigated. Finally, a new approach to the case of two dimensions is presented, using a matrix-transfer technique, where explicit extended states are found.