THERMOELECTRIC-POWER OF ND2-XCEX CUO4 CRYSTALS

We report the in-plane thermopower S of Nd2-xCexCuO4 (0.01 less-than-or-equal-to x less-than-or-equal-to 0.22) crystals for 4 less-than-or-equal-to T less-than-or-equal-to 300 K. In the weakly doped (x approximately 0.01-0.025) samples S is large and negative at high temperature, consistent with electron doping of the CuO2 planes, and approaches zero at low T. Crystals of superconducting and highly doped compositions (x greater-than-or-equal-to 0.15) show a small positive thermopower, with dS/dT < 0. The thermopower of these samples is therefore surprisingly similar, in sign and T dependence, to that of the hole-doped cuprate superconductors.