Coulomb edge states in electronic 2D systems

The details of the structure of edge electron states in bounded charged 2D systems (electron or hole) are discussed. These details are associated with the nonuniformities of the Coulomb electron (hole) density, which are involved in the formation of these states. It is shown that the Coulomb effects at the sharp edges of various 2D systems (in the Corbino and bar geometries) result in the considerable broadening of the conventional magnetic edge levels. In the same formalism, a threshold mechanism is proposed for the appearance of integer “shelves” in the central part of the screened 2D systems. The results are compared with the existing experimental data.