Sr2RuO4的电子相干态：Nernst效应研究  

Coherent electronic states in Sr_2RuO_4,and the Nernst effect

作　　者：许祝安[1] 徐象繁[1] 

机构地区：[1]浙江大学物理系杭州310027

出　　处：《物理》2009年第5期344-348,共5页Physics

基　　金：国家自然科学基金(批准号:10634030,10628408);国家重点基础研究发展计划资助项目

摘　　要：文章首次报道了自旋三重态奇异配对超导体Sr2RuO4的Nernst效应在正常态呈现出的反常行为.在T<100K时,较大的负的Nernst信号出现,其绝对值随温度降低而增大,并在T*≈20—25K时出现一个负的最大值,之后随温度线性减小.这样大的Nernst信号是与正常态的多带性质相关,而非线性的磁场关系则可能与其中的磁涨落相关.文章作者提出在T*温度以下,在电子型的γ带上出现了能带关联的相干态,准粒子的散射受到了抑制,使得在T*温度以下Nernst信号快速减弱.同时,热电势在T*附近出现了拐点,Hall系数开始发散,进一步支持了文章作者提出的观点.We report the first observation of an unusual triplet superconductor Sr2RuO4. Below 100 K, the Nernst Nernst effect in the normal state of the odd-parity spinsignal is negative, and its magnitude increases with decreasing temperature until a maximum is reached around T^＊ ≈ 20-25 K, below which it starts to decrease linearly as a function of temperature. We propose that the large magnitude of the Nernst signal is related to the multiband nature of the normal state and the nonlinearity of the magnetic dependence on magnetic fluctuations. Furthermore, the sharp decrease in the Nernst signal below T^＊ is due to the suppression of quasiparticle scattering and the emergence of band-dependent normal-state coherence in the γ band. The observation of a sharp kink in the temperature dependence of the thermopower around T^＊ and the divergence of the Hall coefficient below T^＊ provide additional support to this picture.

关 键 词：p-波超导体 NERNST效应 电子相干态 

分 类 号：O511[理学—低温物理]