Mechanisms for extra conductance plateaus in quantum wires

Spin-density-functional theory is employed to calculate the conductance G through a quasi-one-dimensional quantum wire. In addition to the usual subband quantization plateaus at ${G=n(2e}^2/h),$ we find additional structures at ${\mathrm{}(n+1/2\mathrm{})(2e}^2/h).\mathrm{}$ The extra structures appear whether or not the electrons in the wire spin polarize. However, only the spin-polarized case reproduces the experimental temperature and magnetic field dependences.