Conductance in magnetic nano-wires

The electrical transport of nano-wires with a constriction is theoretically studied by using the single and two-band tight-binding models. It is shown that the characteristic features of the conductance obtained, such as plateau, oscillation and deviation from the quantized value, can be explained by the electronic state of the constriction, especially the number and the Fermi wavelength of the sub-bands (transverse channels). It is also shown that the minimum quantized conductance e2/h is obtained in ferromagnetic wires when the electronic state of one of the spin channels has a hybridization gap at or near the Fermi level.