MODELS FOR THE INTEGER QUANTUM HALL-EFFECT - THE NETWORK MODEL, THE DIRAC-EQUATION, AND A TIGHT-BINDING HAMILTONIAN

We consider models for the plateau transition in the integer quantum H all effect. Starting from the network model, we construct a mapping to the Dirac Hamiltonian in two dimensions. In the general case, the Dir ac Hamiltonian has randomness in the mass, the scalar potential, and t he vector potential. Separately, we show that the network model can al so be associated with a nearest-neighbor, tight-binding Hamiltonian.