Magnetization of mesoscopic disordered networks

Laboratoire de Physique des Solides, associé au CNRS, Université Paris-Sud - 91405 Orsay, France

Received: 29 November 1996
Accepted: 10 January 1997

Abstract

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 solving the diffusion equation on various types of networks, including a ring with arms, an infinite square network or a chain of connected rings, we deduce the corresponding magnetizations. In the case of an infinite network, the Hartree-Fock average magnetization stays finite in the thermodynamic limit. We discuss the relevance of our results to the experimental situation. Quite generally, when rings are connected, the average magnetization is only weakly reduced by a numerical factor.