新型超导体MgB_2的热电势和电阻率研究  

STUDY ON THE THERMOPOWER AND RESISTIVITY OF A NEW SUPERCONDUCTOR MgB_2

作　　者：杨宏顺[1] 余旻[1] 李世燕[1] 李鹏程[1] 柴一晟[1] 章良[1] 陈仙辉[1] 曹烈兆[1] 

机构地区：[1]中国科学技术大学结构分析实验室物理系,合肥230026

出　　处：《物理学报》2001年第6期1197-1200,共4页Acta Physica Sinica

基　　金：国家重点基础研究经费! (批准号 :19990 64 6)资助的课题&&

摘　　要：测量了MgB2 的热电势和电阻率与温度的依赖关系 .在 10 0K— 30 0K区间 ,热电势呈近似线性温度依赖关系 ,其斜率为正 ,表明载流子为空穴型且与能带贡献的图像相一致 .与此对应 ,在此温区电阻率呈T2 依赖关系 .在 10 0K以下 ,热电势和电阻率各自转变了其高温区的温度依赖关系 .热电势在超导转变温度Te(零电阻 36 6K)到 10 0K间有一宽峰 ,具有声子曳引峰的特征 ,表明电子 声子相互作用很强 .估算了一些重要的参数 ,如带米能EF、能带宽度等 .The temperature-dependent thermopower and resistivity of MgB2 were measured. In the range of 100-300K, the ther mopower presents positive nearly linear temperature dependence, indicating that the charge carrier is hole and it is consistent with the energy band pattern. In contrast, the resistivity follows T-2 relationship in the same temperature range. Below 100K, ther mopower and resistivity change their temperature dependence. The thermopower presents a hump between the superconducting transition temperature T-c (zero resistance, 36.6K) and 100K. It has the characteristic of the phonon drag,indicating the strong electron-phonon interaction. Some important parameters are estimated according to experimental results,such as Fermi energy E, and energy band width.

关 键 词：新型超导体 热电势 电阻率 温度 

分 类 号：O511[理学—低温物理]