HOMOGENEOUS AND INHOMOGENEOUS STATES OF A 2-DIMENSIONAL ELECTRON LIQUID IN A STRONG MAGNETIC-FIELD

A theory of linear screening by a two-dimensional electron liquid in a strong magnetic field is formulated quantitatively. It takes into account electron-electron interaction and it is valid in the limit of small q. The results of the theory, including the negative sign of the screening radius, are shown to be confirmed by magnetocapacitance experiments. Near the fractional quantum Hall states the screening length tends to infinity, and the long-range potential of the remote donors makes the electron liquid very inhomogeneous. Different manifestations of this effect are discussed.