ON THE RESPONSE OF COMPOSITE FERMIONS TO WEAK ELECTROSTATIC POTENTIALS

We establish that the response to static perturbations of two-dimensional electron systems (2DESs), exposed to magnetic field B, in states with the Landau-level filling fractions νe close to one such as 1/2, is singularly different from that of 2DESs at small ‖B‖. Thus in addition to demonstrating the severe inadequacy of the treatment of composite fermions as non-interacting particles, we show, in contradiction to a recent theoretical finding, that the physical origin of the observed behavior of the dc longitudinal magneto-resistivity for νe≈1/2 in periodically modulated 2DESs remains to be determined.