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arXiv 1303.4416cond-mat.supr-con
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CeCoIn5中重费米子的库珀对成像

Imaging Cooper Pairing of Heavy Fermions in CeCoIn5

M. P. Allan, F. Massee, D. K. Morr, J. van Dyke, A. W. Rost, A. P. Mackenzie, C. Petrovic, J. C. Davis

摘要:

重费米子超导体的库珀配对机制,虽然长期假设是由于自旋涨落,尚未确定。超导能隙delta(k)的动量空间(k空间)结构编码了这种配对机制的细节。然而,由于能量标度如此之低,不可能直接测量任何重费米子超导体的δ(k)。Bogoliubov准粒子干涉(QPI)成像是一种用于测量高Tc超导体能隙的成熟技术,最近被提出作为测量重费米子超导体(特别是CeCoIn 5)中δ(k)的新方法。通过实施这种方法,我们立即检测到一个超导能隙,其节点沿k方向取向||(+-1,+-1)pi/a0方向。此外,我们还确定了重费米子超导体δ(k)的完整k空间结构。对于CeCoIn 5,这种新的信息包括:复杂的能带结构和费米表面的杂化重带,最高的幅度delta(k)打开的高k带,使间隙节点出现在相当意外的k空间位置的事实,和Bogoliubov准粒子干涉图案是最符合dx 2-y2间隙对称性。这种定量的重能带和带隙结构数据的可用性将是至关重要的,在确定这种材料中的重费米子超导性的微观机制,也许在一般情况下。

英文摘要:

The Cooper pairing mechanism of heavy-fermion superconductors, while long hypothesized as due to spin fluctuations, has not been determined. It is the momentum space (k-space) structure of the superconducting energy gap delta(k) that encodes specifics of this pairing mechanism. However, because the energy scales are so low, it has not been possible to directly measure delta(k) for any heavy-fermion superconductor. Bogoliubov quasiparticle interference (QPI) imaging, a proven technique for measuring the energy gaps of high-Tc superconductors, has recently been proposed as a new method to measure delta(k) in heavy-fermion superconductors, specifically CeCoIn5. By implementing this method, we immediately detect a superconducting energy gap whose nodes are oriented along k||(+-1, +-1)pi/a0 directions. Moreover, we determine the complete k-space structure of the delta(k) of a heavy-fermion superconductor. For CeCoIn5, this novel information includes: the complex band structure and Fermi surface of the hybridized heavy bands, the fact that highest magnitude delta(k) opens on a high-k band so that gap nodes occur at quite unanticipated k-space locations, and that the Bogoliubov quasiparticle interference patterns are most consistent with dx2-y2 gap symmetry. The availability of such quantitative heavy band- and gap-structure data will be critical in identifying the microscopic mechanism of heavy fermion superconductivity in this material, and perhaps in general.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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