Spin polarization in a model quantum wire with a cross-section

Numerical investigation of the electronic structure of a small closed quantum system fabricated on the two-dimensional electron gas forming on the interference between GaAs and AlxGa1-xAs is reported. The Kohn-Sham spin-density-functional theory is applied. Self-consistent results show that the quantum system assumes unequal numbers of electrons for spin up and spin down because of the existence of bound states. The profiles of effective potential energies for spin up and spin down electrons are then found to be very different, which will result in different transmission coefficients. It is notable that this spin polarization is caused by the geometry of the nanostructure.