Electrical Transport Properties of the Purple Bronze Li$_{0.9}$Mo$_6$O$_{17}$

The crossover from metallic to semiconductor-like behavior in Li$_{0.9}$Mo$_6$O$_{17}$ has been the subject of intense discussion. An important issue is whether or not it is a Luttinger Liquid. This idea has received substantial support because of the quasi-one dimensionality observed in electrical resistivity measurements performed 20 years ago. In this work the transport properties of Li$_{0.9}$Mo$_6$O$_{17}$ single crystals are revisited. Crystals were characterized by x-ray powder diffractometry and the crystallographic orientations were determined by transmitted Laue diffraction. Electrical resistance as a function of temperature, $R(T)$, performed using standard four probe and Montgomery methods are compared. The magnetic field dependence of the minimum in the $R(T)$ curves and the temperature dependence of the insulating-like regime are also presented.