Nonmetallic power-law behavior of conductance in Ni-doped NbSe3 nanowires

Abstract

We report on diverse transport properties observed in NbSe3 nanowires of dilute Ni concentrations, where the resistance of some nanowires retains metallic behavior with regions of negative absolute resistance and switching transition showing up in current-voltage curve at sufficiently low temperatures, while others demonstrate metal-insulator transitions below the first charge density wave (CDW) transition. The temperature and voltage dependence of the resistance for the nonmetallic samples are governed by power laws; however, the anomalous features of the CDW transitions still retain. The observed transport behaviors are apparently due to the variation of potential along the conducting channel caused by different kinds of nonuniformities. A phenomenological model with one-dimensional phase slippage occurring in the certain segment of the nanowire, where Friedel oscillations-enhanced local CDW domains cluster altogether over the whole cross section, is presented as the possible mechanism for the nonmetallic power-law behavior. Our work sheds new light on the possible origin of nonmetallic power-law behavior in NbSe3, which has been under debate for a long time.