TRANSPORT-PROPERTIES OF ND1.85CE0.15CUO4-DELTA SINGLE-CRYSTALS - THE NARROW-BAND MODEL

The anisotropy of the resistivity and thermoelectric power (TEP) S of Nd1.85Ce0.15CUO4-delta single crystal (T-c = 17 K) has been investigat ed. In the temperature range T-c < T < 300 K the ratio rho(c)/rho(ab) approximate to 10(4) and the dependences rho(ab) (T) and rho(c) (T) ch ange from quadratic to linear at T similar to 200 K. The dependences S -ab (T) and S-c (T) reach a maximum at T > T-c and then decrease almos t linearly with increasing temperature, changing sign from positive to negative near T similar to 150 K. The features of the resistivity and TEP temperature dependences (the law rho proportional to T-2 changing to rho proportional to T, the change in the sign of S with temperatur e, and the low TEP anisotropy at large rho anisotropy) have been inter preted in the framework of the narrow-band model.