Physical Review B 75,15 (2007) 155305;
We discuss a general form of the exchange energy for a homogeneous system of interacting electrons in two spatial dimensions, which is particularly suited in the presence of a generic spin-orbit interaction. The theory is best formulated in terms of a generalized fractional electronic polarization. Remarkably, we find that a net generalized polarization does not necessarily translate into an increase in the magnitude of the exchange energy, a fact that, in turn, favors unpolarized states. Our results account qualitatively for the findings of recent experimental investigations.
Physics, Condensed Matter
Date of this Version