Evidence for influence of the interactions between electrons on the chemical potential of a two-dimensional electron gas

It is shown experimentally that the interactions between electrons strongly influence the chemical potential of the two-dimensional electron gas. At sufficiently low temperatures and in high magnetic fields regions of filling factor appear where (i) the chemical potential diminishes with increasing carrier density, and (ii) the rate of increase of the chemical potential with magnetic field is much higher than the maximum value for a noninteracting gas. Using these results we have estimated the energy of the electron-electron interaction in Si inversion layers which appears to be an order of magnitude less than the classical Coulomb interaction calculated for Si-MOSFET's. (orig.)