Spin-dependent electron behaviour in quantum point contacts

The effect of spontaneous spin polarization in quantum point contacts (QPCs ) is investigated by self-consistent modelling within the Kohn-Sham local s pin-density formalism. The existence of the spin-polarized state of the QPC channel in the low-density regime is shown to change the value and the sha pe of the effective potential barrier for up- and down-spin electrons. We s uggest that this effect can be relevant to the explanation of the anomalous 0.7-structure in the QPC conductance and may assist spin injection in pote ntial spintronic devices.