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 (n+1/2)(2e(2)/h). 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.