Spontaneous polarization of quantum dots

We have performed spin density functional theory calculations to determine the electronic structure of lateral GaAs-AlGaAs quantum dots. We have developed a highly efficient, quasi-adiabatic subband method which allows us to solve the Schrodinger equation for dot electron number N/spl lsim/200. We find that the direct Coulomb energy of putting two electrons into up and down spin of the same spatial state at the Fermi surface, combined with the polarization dependent, exchange-correlation induced splitting of the spin levels, typically exceeds the average single particle level spacing and leads to spontaneous spin polarization of the dot.