【摘要】 本文测量了电子型高温超导体Nd_1.85Ce_0.15CuO_4-δ单晶在不同退火条件下的ab面电阻率（ρ）和热电势（S）.电阻率曲线偏离了费米液体理论T2的温度依赖关系和热电势在整个测量温区（15～300K）都为正值表明在这一体系中有两种载流子共存.基于此,我们提出了一个空穴型窄带叠加在一个电子型宽带的双能带模型.进一步的退火处理实验表明:这一理论模型能很好的解释电阻率和热电势在不同退火条件下的行为,并有助于我们分析在不同退火过程中能带的结构和填充位置的变化.在深度去氧退火过程中,能带结构保持不变的但能带填充度增加使得费米能（EF）上升了;在加氧退火过程中EF位置不变而空穴型窄带变宽了.更多还原

【Abstract】 The in-plane resistivities(ρ) and thermopower(S) are studied in the Nd1.85Ce0.15CuO4+δ single crystals under different annealing conditions.In the optimally annealed samples,a positive thermopower indicates the existence of a holelike band.The resistivity and thermopower behaviors can be well described in a two-band model characterized by the different relaxation time(i.e.τh∝T-1 in holelike band and τe∝T-2 in electronic band).Moreover,the band shape is nearly unchanged and the Fermi level(EF) rises after the samples further deoxygenated.In contrast,the width of holelike band has been broadened and the Fermi level is nearly unchanged after the further oxygenation process.更多还原