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arXiv 0904.0388cond-mat.supr-concond-mat.str-el
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热输运对超导能隙结构的探测

Heat transport as a probe of superconducting gap structure

H Shakeripour, C Petrovic, Louis Taillefer

摘要:

超导能隙的结构为研究序参量的对称性和配对机制提供了重要线索。由对称性引起的间隙函数中节点的存在意味着非常规的序参量,而不是s波。在这里,我们展示了如何在非常低的温度下测量热导率可以用来确定是否存在这样的节点在一个特定的超导体,并阐明其性质和位置。我们专注于T趋于0时的剩余线性项。零磁场中的有限值是杂质强加节点的强有力证据,并且对杂质散射的依赖性可以区分节点的线或点节点。应用磁场探测低能准粒子激发,无论是与节点或与费米表面某个部分上的小间隙值相关,如在多带超导体中。我们围绕原型材料进行讨论:Nb用于s波,Tl2Ba2CuO(6+δ)用于d波,Sr2RuO4用于p波,NbSe 2用于多带超导。在此框架下,我们讨论了三种重费米子超导体:CeIrIn 5,CeCoIn 5和UPt 3。

英文摘要:

The structure of the superconducting gap provides important clues on the symmetry of the order parameter and the pairing mechanism. The presence of nodes in the gap function imposed by symmetry implies an unconventional order parameter, other than s-wave. Here we show how measurements of the thermal conductivity at very low temperature can be used to determine whether such nodes are present in a particular superconductor, and shed light on their nature and location. We focus on the residual linear term at T goes to 0. A finite value in zero magnetic field is strong evidence for symmetry-imposed nodes, and the dependence on impurity scattering can distinguish between a line of nodes or point nodes. Application of a magnetic field probes the low-energy quasiparticle excitations, whether associated with nodes or with a small value of the gap on some part of the Fermi surface, as in a multi-band superconductor. We frame our discussion around archetypal materials: Nb for s-wave, Tl2Ba2CuO(6+δ) for d-wave, Sr2RuO4 for p-wave, and NbSe2 for multi-band superconductivity. In that framework, we discuss three heavy-fermion superconductors: CeIrIn5, CeCoIn5 and UPt3.

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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