PEIERLS PHASE TRANSITION AND NONLINEAR TRANSPORT STUDY OF DOPED BLUE BRONZES K0.3-xNaxMoO3

Abstract

Temperature dependence of Ohmic resistance, and nonlinear current–voltage (I–V) characteristics at 77 K were systematically studied in pure potassium blue bronze K 0.3 MoO 3 and Na-doped alloy bronzes K 0.3-x Na x MoO 3(x = 0.02, 0.05, 0.10). No considerable influence of Na ions doping in K 0.3 MoO 3 was found on the Peierls transition temperature, while obvious enchancement on semiconductor gap and remarkable influence on the first threshold field were observed. We attribute the first phenomenon to two opposite effects of Na ions, and the depinning model is proposed to account for the latter. The analytical form of nonlinear charge-density wave current I CDW in a moderate field range fits the power-law relation, i.e. I CDW ∝ (V/V T -1)α, where the exponent α is about 3/2 and slightly enhanced by Na ions doping.