Kuroki Kazuhiko, Tanaka Yukio, Arita Ryotaro
Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan.
Phys Rev Lett. 2004 Aug 13;93(7):077001. doi: 10.1103/PhysRevLett.93.077001. Epub 2004 Aug 11.
We propose that the spin-triplet pairing mechanism due to disconnected Fermi surfaces proposed in our previous study [Phys. Rev. B 63, 174507 (2001)]] may be at work in a recently discovered superconductor NaxCoO2.yH2O. We introduce a single band effective model that takes into account the pocketlike Fermi surfaces along with the van Hove singularity near the K point found in the band calculation results. Applying the fluctuation exchange method and solving the linearized Eliashberg equation, the most dominant pairing is found to have spin-triplet f-wave symmetry, where the nodes of the gap function do not intersect the pocket Fermi surfaces. The presence of finite Tc is suggested in sharp contrast to cases when the gap nodes intersect the Fermi surface.
我们提出，在我们之前的研究[《物理评论B》63, 174507 (2001)]中提出的由于不相连费米面导致的自旋三重态配对机制，可能在最近发现的超导体NaxCoO2.yH2O中起作用。我们引入了一个单带有效模型，该模型考虑了袋状费米面以及在能带计算结果中发现的K点附近的范霍夫奇点。应用涨落交换方法并求解线性化的埃利亚什贝格方程，发现最主要的配对具有自旋三重态f波对称性，其中能隙函数的节点不与袋状费米面相交。与能隙节点与费米面相交的情况形成鲜明对比的是，这里暗示了有限Tc的存在。
