Two‐dimensional systems

Nearly all the microscopically small devices that are contributing to the “microtechnological” revolution are composed of thin layers of materials. Such devices are nearly two‐dimensional, and many of the questions concerning the ultimate possibilities and limitations of the technology will require investigation of the physical processes in two dimensions. Similarly, questions that arise in such diverse fields as surface physics, membrane biology and catalytic chemistry involve two‐dimensional phenomena. At least as important as these practical questions is simple intellectural curiously: How does Nature behave in a world of limited dimensionality?