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arXiv 0706.1376cond-mat.supr-concond-mat.str-el
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重费米子-金属/超导体结的点接触Andreev反射谱

Point-contact Andreev reflection spectroscopy of heavy-fermion-metal/superconductor junctions

W. K. Park, H. Stalzer, J. L. Sarrao, J. D. Thompson, L. D. Pham, Z. Fisk, J. Frederick, P. C. Canfield, L. H. Greene

摘要:

我们之前使用Au尖端对重费米子超导体CeCoIn $_5$的点接触Andreev反射研究显示了两个明显的特征:降低的Andreev信号和不对称的背景电导[1]。为了探索它们的物理起源,我们已经将我们的测量扩展到单晶重费米子金属和超导Nb尖端之间的点接触结。微分电导谱上采取的结与三个重费米子金属,CeCoIn $_5$,CeRhIn $_5$,和YbAl $_3$,每一个具有不同的电子质量。与Au/CeCoIn $_5$结相比,Andreev信号没有降低,并且没有观察到对有效质量的依赖性。基于重费米子的双流体图像提出了一种可能的解释。[1]W. K. Park等人,Phys. Rev. B 72 052509(2005); W. K. Park等人,Proc. SPIE-Int. Soc.Opt.Eng.593259321Q(2005); W. K. Park等,Physica C(印刷中)(cond-mat/0606535)。

英文摘要:

Our previous point-contact Andreev reflection studies of the heavy-fermion superconductor CeCoIn$_5$ using Au tips have shown two clear features: reduced Andreev signal and asymmetric background conductance [1]. To explore their physical origins, we have extended our measurements to point-contact junctions between single crystalline heavy-fermion metals and superconducting Nb tips. Differential conductance spectra are taken on junctions with three heavy-fermion metals, CeCoIn$_5$, CeRhIn$_5$, and YbAl$_3$, each with different electron mass. In contrast with Au/CeCoIn$_5$ junctions, Andreev signal is not reduced and no dependence on effective mass is observed. A possible explanation based on a two-fluid picture for heavy fermions is proposed. [1] W. K. Park et al., Phys. Rev. B 72 052509 (2005); W. K. Park et al., Proc. SPIE-Int. Soc. Opt. Eng. 5932 59321Q (2005); W. K. Park et al., Physica C (in press) (cond-mat/0606535).

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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