Abstract
The density of states of a two-dimensional electron gas is calculated in the weak-disorder limit by taking into account self-consistent screening and Landau-level coupling effects. The resultant density of states is broad with considerable overlap between Landau levels, being strikingly different from the well-separated sharp levels of the standard short-range impurity-scattering model. In qualitative agreement with a number of recent experimental findings, calculated level broadenings are much larger than that implied by the zero-field mobility.