Many body effects at surfaces and interfaces

The past two decades have experienced the development of angle-resolved photoemission to the point that it can now provide crucial information on an energy scale that is relevant to many key problems in condensed matter physics. At the same time, our ability to prepare and characterize surfaces, interfaces, and thin films has improved to the extent that many exotic phases can be produced with a high degree of perfection. The combination of these two developments suggests many interesting experiments can be performed that probe the coupling between charge, lattice, and spin degrees of freedom in the context of surface and interface physics. In this paper we briefly review a few groundbreaking experiments that have initiated this effort. We also speculate on future developments in this area. (C) 2001 Elsevier Science B.V. All rights reserved.