THE METAL-INSULATOR-TRANSITION - A PERSPECTIVE

The metal-insulator transition, a quantum phase transition signifying the natural transformation of a metallic conductor to an insulator, co ntinues to be the focus of intense inquiry and debate. The first discu ssion of the heuristic differences between metals and insulators, and implicitly the critical conditions for the transition between these ca nonical electronic regimes, dates back to the dawn of the twentieth ce ntury. As we approach the end of the century, the precise nature of th e metal-insulator transition remains one of the major intellectual cha llenges in condensed matter science. In this article we present a brie f introduction to just some of the key underlying features of this end uring physical phenomenon. The following articles and discussion prese nt a detailed current account of the many facets of the science of the metal-insulator transition.