高Tc超导体的室温飞秒时间分辨谱研究  

Room Temperature Femtosecond Time-Resolved Spectroscopy in High Tc Superconductors

作　　者：皮飞鹏[1] 曾文生[1] 朱德瑞[1] 林位株[1] 莫党[1] 

机构地区：[1]中山大学物理学系

出　　处：《中山大学学报（自然科学版）》1994年第2期63-68,共6页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家自然科学基金;国家超导研究发展中心资助项目

摘　　要：本文研究了室温下ＹＢａ_２Ｃｕ_３Ｏ_（７－ｘ）（ｘ＝０．１，０．４，０．８）和ＰｒＢａ_２Ｃｕ_３Ｏ_（６．９）外延膜的飞秒瞬态反射谱。结果表明，瞬态反射信号△Ｒ（ｔ）的符号和弛豫时间与载流子浓度密切相关，对超导的ＹＢａ_２Ｃｕ_３Ｏ_（６．９），样品进行不同程度的去氧处理或者用Ｒｒ替代Ｙ后，△Ｒ（ｔ）的符号由正变负，弛豫时间由小于１００ｆｓ增加到大于１ｐｓ，说明在高Ｔｃ氧化物超导体中，载流子浓度的减少使载流子－声子耦合强度降低。Femtosecond time- resolved reflection spectroscopy in high Tc oxide super-conductors YBa_2Cu_3O_(7-x)(x=0.1,0.4,0. 8) and PrBa_2Cu_3O_(6.9) is studied. It is observedthat the signs and the relaxation times of the reflectivity signals △R(t)are related tothe carrier concentration, The signs of △R(t)in YBa_2Cu_3O_(7-x) are found to change frompositive(x=0.1) to negative and the relaxation times are measured to increase fromless than l00 fs to more than 1 ps, with increasing x and with substitution of Pr for Y.These results reveal that the carrier-phonon coupling reduces with the decrease of the carrier concentration.

关 键 词：高TC 超导体 飞秒脉冲 时间分辨谱 

分 类 号：O511.1[理学—低温物理]