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摘要: 本文解释了La2CuO4+(00.09)和La2-xSrxCuO4(0x0.3)两种p型系统含铜稀土氧化物中的电阻和Seebeck系数与温度的依赖关系,在室温以上,一氧大气压下的La2CuO4+系统趋于失氧;在500 K以上,超导样品显示出失氧的一级相变,并且恢复到反铁磁相。在转变温度T1300 K以下,对00.05成份的样品,相分离成反铁磁相和超导相;而在TcTT100 K的温度范围内,超导相进一步分离成富空穴和贫空穴畴。在0.040.09范围内,Tc处的电阻陡降出现了台阶;我们认为,它反映了电子成对的起伏。在La2-xSrxCuO4系统中,对于成分为0x0.2的样品,在T1300 K以上,空穴的运动是弥散的,但是Hm=0;而对于x0.22的样品,经历了从平滑到Fermi液态的转变。成份为0x0.12时,在TcTT1范围(其中空穴继续以弥散方式运动)是亚稳的,但是,在TcTT150 K范围,出现了电荷起伏。当样品冷却通过T1时,对于成份为0.15x0.2的样品,经历了由弥散到强质量增强巡游电子状态的转变;在Tc处,从均匀的修饰电子的正常态凝聚成超导的载流子对。在超导成份样品的正常态中,不寻常的电子-晶格相互作用,可以归结为在CuO2面上从更离子性的到共价性的Cu:3dx2-r2─O:P键合的转变;通过这种转变,轨道杂化和Hubbard U参量随Cu─O键长和Cu原子上的外表局域氧化态都产生灵敏的变化。Abstract: The temperature dependence of the resistivity and Seebeck coefficient for the two p-type systems La2CuO4+ (00.09) and La2-xSrxCuO4 (0x0.3) are interpreted.
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Key words:
- La2CuO4+ /
- La2-xSrxCuO4 /
- resistance vs temperature /
- Seebeck coefficient /
- phase segregation /
- charge fluctuation
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