Anomalous saturation of the phase coherence length in underdopedPr2−xCexCuO4thin films

Abstract

We present a quantitative analysis of the magnetoresistance of nonsuperconducting ${\mathrm{Pr}}_{2-x}{\mathrm{Ce}}_x{\mathrm{CuO}}_4$ using fits to two-dimensional weak-localization theory, and extract the temperature dependence of the phase coherence length. This characteristic length scale saturates at low temperatures, correlating with deviations of the in-plane resistivity from ${\rho }_{\mathrm{xx}}\propto \ln \mathrm{}(1/T)\mathrm{}$ behavior also observed in these materials. A comparison with ${\mathrm{Nd}}_{1.90}{\mathrm{Ce}}_{0.10}{\mathrm{CuO}}_4,$ which shows no saturation, is also presented.