Breakup of a Dimer: a New Approach to Localization Transition

Within the framework of tight binding models, aperiodic systems are mapped to a renormalized lattice with a dimer defect. In models exhibiting metal-insulator transition, the dimer acts like a resonant cavity and explains the existence of the ballistic transport in the system. The localization in the model can be attributed to the vanishing of the coupling between the two sites of the dimer. Our approach unifies Anderson transition and resonance transition and provides a new formulation to understand localization and its absence in aperiodic systems.