MgB_2及高温超导体的强电子声子耦合和输运性质  

STRONG ELECTRON-PHONON COUPLINGAND THE RESISTIVE TRANSITION INMgB_2 AND HIGH TEMPERATURE SUPERCONDUCTORS

作　　者：尹道乐[1] 齐志[1] 许恒毅[1] 王福仁[1] 李传义[1] 

机构地区：[1]北京大学物理学院,北京100871

出　　处：《低温物理学报》2001年第4期261-268,共8页Low Temperature Physical Letters

基　　金：国家重点基础研究专项经费 (NKBRSF G 19990 6 40 )资助项目

摘　　要：我们对MgB2 和高临界温度的铜氧化合物超导体进行了对比研究 .MgB2 显示出以声子为媒介的BCS超导体的典型行为 .对所谓的McMillan Hopfield系数的解析表达暗示具有高角动量l的导带l(l± 1)杂化对强BCS超导体有利 .我们还分析讨论了高临界温度铜氧化物和MgB2 的传输性质 ,发现一个统一的R(T ,H)方程 ,可以很好地描述与MgB2 和YBCO无孪单晶在B 8T的宽场强范围内的正常态 超导电阻转变 .We make a comparative study of MgB-2 and high critical temperature cuprates. MgB-2 shows typical behavior of phonon-mediated BCS superconductivity. The analytical expression for the so-called McMillan-Hopfield parameter implies that the l(l ±1) hybridization of conduction band with high angular momentum l is beneficial for strong BCS superconductivity. The resistive transitions of high critical temperature cuprates and MgB-2 near and below critical temperature are studied. A model R(T,H) equation fairly agrees with the experimental data of the untwined YBCO crystals as well as high critical temperature MgB-2.

关 键 词：MGB2 硼化镁 高温超导体 电声耦合 输运性质 

分 类 号：O511[理学—低温物理]