【摘要】 测量了名义组分为 BaxLa_5-xCu₅O_5（3-y）（x=0,0.25,0.5,1.0,1.25,1.5; y>0）的系列样品电阻-温度关系。发现:对x=0的二元氧化物,其电子输运呈典型的半导体特征;随着Ba的掺入以及含Ba量的增加,系统经历了半导体-半金属-金属（超导体）转变,并且其超导临界温度Tc也单调地升高。根据Mattheiss及Freeman等人的能带计算结果,在电声子强耦合的框架里对上述现象作了定性的解释。本文作者认为:二价Ba的掺入抑制了晶格的不稳定性,稳定了超导相。更多还原

【Abstract】 The temperature dependence of resistance of specimens with the nominal composition Ba_xLa_5-xCu₅O_5（3-x）（x=0, 0.25, 0.5, 1.0, 1.25, 1.5; y>0） were measured. It was found that the binary oxide with x = 0 is a typical semiconductor, and the transition from semiconductor to semimetal, finally to metal （superconductor）, occurs respectively in this system as x increased. Also the critical temperature of superconducting transition, Tc is elevated monotonously by increasing concentration of Ba. From the results of the energy bands calculated by Mattheiss and Freeman, a qualitative explanation is given according to the strong electron-phonon coupling theory. It is suggested that the addition of divalent barium in La2CuO4 suppress the instability and stabilizes the superconducting phase.更多还原