Density dependence of critical magnetic fields at the metal-insulator bifurcation in two dimensions

Abstract

The density dependence of the critical in-plane magnetic field B c at the bifurcation of the resistivity of two-dimensional electron systems with low levels of disorder is determined using the spin-polarization dependenceof the electron exchange-correlation hole. Recent numerical simulation results for ground-state energies also permit determination of the magnetic field B p o l (n) needed to saturate the spin polarization. The resulting picture gives a good account of reported experimental results for B c as a function of electron density in p-type GaAs systems and indicates that the interactions between electrons play a crucial role in the bifurcation phenomenon.