Temperature and voltage driven tunable metal-insulator transition in individual W_xV_1-xO₂ nanowires

Results from transport measurements in individual W_xV _1-xO₂ nanowires with varying extents of W doping are presented. An abrupt thermally driven metal-insulator transition (MIT) is observed in these wires and the transition temperature decreases with increasing W content at a pronounced rate of -(48-56) K/at.% W, suggesting a significant alteration of the phase diagram from the bulk. These nanowires can also be driven through a voltage-driven MIT and the temperature dependence of the insulator-to-metal and metal-to-insulator switchings are studied. While driving from an insulator to metal, the threshold voltage at which the MIT occurs follows an exponential temperature dependence [V_THexp(-T/T ₀)], whereas driving from a metal to insulator, the threshold voltage follows V_TH√T_c-T and the implications of these results are discussed.