Spin polarization in a two-dimensional electron gas

We evaluate the charge and longitudinal spin response functions of a two-dimensional electron gas with e(2)/r interactions in an arbitrary state of spin polarization, using a structurally self-consistent approach to treat exchange and correlation and to demonstrate their roles in regard to the stabilization of spin-polarized states. From the results, we assess the nature of the magnetic order in the electronic ground state in zero-magnetic field as a function of electron density. We find that states of partial spin polarization are thermodynamically unstable at all values of the coupling strength and that a first-order quantum phase transition occurs with increasing coupling strength from the magnetically disordered (paramagnetic) phase to the fully spin-polarized (ferromagnetic) phase. This behaviour is consistent with diffusion Monte Carlo data, although the location of the phase transition is underestimated in our calculations. (C) 2002 Elsevier Science B.V. All rights reserved.