Peierls phase transition and nonlinear transport study of doped blue bronzes K0.3-xNaxMoO3

Temperature dependence of Ohmic resistance, and nonlinear current-voltage ( I-V) characteristics at 77 K were systematically studied in pure potassium blue bronze K0.3MoO3 and Na-doped alloy bronzes K0.3-xNaxMoO3 (x = 0.02, 0. 05, 0.10). No considerable influence of Na ions doping in K0.3MoO3 was foun d on the Peierls transition temperature, while obvious enchancement on semi conductor gap and remarkable influence on the first threshold field were ob served. We attribute the first phenomenon to two opposite effects of Na ion s, and the depinning model is proposed to account for the latter. The analy tical form of nonlinear charge-density wave current I-CDW in a moderate fie ld range fits the power-law relation, i.e. I-CDW proportional to (V/V-T - 1 )(alpha), where the exponent alpha is about 3/2 and slightly enhanced by Na ions doping.