Two-Dimensional Interface Electron Systems

Abstract

The electrostatic charging of dielectrics with surface-bound electrons is an everyday occurrence of our life. The essence of the phenomenon is very simple: a dielectric body attracts free electrons and gathers them at its surface, forming a simple capacitor. For a long while, such interface electrons were of minor interest for fundamental physics because small surface irregularities trap them in the plane of the interface owing to the strong polarization forces. Even a single atom at a flat surface can capture an electron, forming a motionless negative ion. Only at the end of the 1960s was it understood that liquid helium, as a dielectric substrate, provides unique possibilities for studying highly correlated two-dimensional (2D) electron systems.