Low-temperature heat transport of Nd_{2-x}Ce_{x}CuO_{4} single crystals

Abstract

We report a study of the Ce doping effect on the thermal conductivity (\kappa) of Nd_{2-x}Ce_{x}CuO_{4} (NCCO) at low temperatures down to 0.3 K and in magnetic fields up to 14 T. It is found that with Ce doping, the electronic thermal conductivity increases; at the same time, the a-axis field induced changes in \kappa(H), associated with the spin flop and spin polarization of Nd^{3+} sublattice, and the spin flop of Cu^{2+} sublattice, gradually disappear. These are clearly due to the electron doping and the destruction of the antiferromagnetic orders. In the superconducting NCCO with x = 0.14 and 0.18, although the electronic thermal conductivity shows sizable field dependencies with H // c, the paramagnetic scattering of phonons is still playing the dominant role in the heat transport, which is different from many other cuprates. In the lightly doped samples (x = 0.03 and 0.06), the low-T \kappa(H) isotherms with H // c show a step-like anomaly and is likely related to the spin/charge stripes.