Nanostructures. An introduction

The subjects for this workshop were nanostructures and quasi-two-dimensional systems. Artificial nanostructures have structure on the scale of nanometres (10~9 m). The nanometre represents a limit on the miniaturisation of artificial structures since atomic diameters are of this scale. Two-dimensional systems are atomically thin layers, usually of electrons embedded in a semiconductor substrate. These fascinating systems owe their existence to the rapid advances within the last ten years in electronic device miniaturisation and manufacture. Spectacular as the technological advances have been, the focus of the workshop was not on these achievements themselves, but on the opportunities the technology provides to think up and build artificial systems having exotic physical properties that give us insight into structure on a quantum scale. Since the atomic scale is determined by the dictates of quantum mechanics it is not surprising that artificial structures on this scale should have properties which are dominated by quantum mechanical effects and strong correlations, and that these often generate novel ground states.