Magnetization of Mesoscopic Disordered Networks

We study the magnetic response of mesoscopic metallic isolated networks. We calculate the average and typical magnetizations in the diffusive regime for non-interacting electrons or in the first order Hartree-Fock approximation. These quantities are related to the return probability for a diffusive particle on the corresponding network. By solution of the diffusion equation on various types of networks, including a ring with arms or an infinite square network, we deduce the corresponding magnetizations. In the case of an infinite network, the Hartree-Fock average magnetization stays finite in the thermodynamic limit.