Effect of exchange and correlation on the Fermi momenta of an electron liquid in a magnetic field

We show that in the three-dimensional interacting electron liquid in a magnetic field, with more than one Landau subband occupied, the Fermi momenta of the various subbands differ from those of the noninteracting electron gas. We calculate the interacting Fermi momenta including exchange and correlation in the random-phase approximation. It is shown that the change of Fermi momenta leads to novel behavior of the spin polarization as a function of magnetic field, which should be observable in experiments on wide parabolic quantum wells.