THERMODYNAMICS AND TRANSPORT IN MESOSCOPIC DISORDERED NETWORKS

We describe the effects of phase coherence on transport and thermodyna mic properties of a disordered conducting network. In analogy with the weak-localization correction, we calculate the phase coherent contrib ution to the magnetic response of mesoscopic metallic isolated network s. It is related to the return probability for a diffusive particle on the corresponding network. By solving the diffusion equation on vario us types of networks, including a ring with arms, an infinite square n etwork or a chain of connected rings, we deduce the magnetic response. As is the case for transport properties (weak-localization correction s or universal conductance fluctuctions) the magnetic response can be written in terms of a single function S called the spectral function w hich is related to the spatial average of the return probability on th e network. We have found that the magnetization of an ensemble of conn ected rings is of the same order of magnitude as if the rings were dis connected.