Dynamic quantum Hall effect

The Hall response sigma-subscript H(omega) of a two-dimensional electron impurity system in a quantizing magnetic field at a frequency omega which does not equal zero is analyzed. The response sigma-subscript H(omega) is predicted to have a dip in its functional dependence on the concentration. The dip results from the filling of localized states and may actually consist of two dips. When the Landau level is completely filled, sigma-subscript H(omega) is approximately the same as the response of the pure system.