UNUSUAL BAND EFFECTS IN A 2D LATTICE - SUPERCONDUCTING PROPERTIES OF ARTIFICIAL NETWORKS AND SINGLY CONNECTED DOTS

Superconductivity offers an unique example in condensed matter physics where a quantum state is occupied coherently over macroscopic distances. We review some recent studies on artificial 2D superconducting microstructures including periodic and nonperiodic submicron wire networks and small superconducting dots. By measuring the phase boundary between the superconducting and normal state, the equilibrium magnetization, the magnetoresistance or the critical current, one can trace back to the spectral properties of a quantum particle on the underlying 2D lattice. Through a few examples of such superconducting model systems we illustrate some remarkable properties of Landau levels in periodic systems, as well as quantization effects in singly connected dots. © 1990.