Resistance, Magnetoresistance, and Thermopower of Zinc Nanowire Composites

We report a very large enhancement of the thermopower of 4 nm diameter metallic Zn nanowires, with a temperature dependence that is consistent with that of their electrical resistivity and the Mott formula. The temperature dependence of the resistance, magnetoresistance, and thermopower of composites consisting of 15, 9, and 4 nm diameter Zn nanowires imbedded in porous host materials is reported. The 15 nm wires are metallic. The smaller wires show 1D weak localization, but the electrical resistivity mostly follows a $T^{-1/2}$ law, and the thermopower of the 4 nm wires saturates at $-130\mu \mathrm{V}/\mathrm{K}$.