Andreev reflection spectroscopy evidence for multiple gaps in MgB2 -: art. no. 064513

被引：24
|
作者：
Li, ZZ [1 ]
Tao, HJ [1 ]
Xuan, Y [1 ]
Ren, ZA [1 ]
Che, GC [1 ]
Zhao, BR [1 ]
机构：
[1] Chinese Acad Sci, Ctr Condensed Matter Phys, Beijing 100080, Peoples R China
来源：
PHYSICAL REVIEW B | 2002年 / 66卷 / 06期
关键词：
D O I：
10.1103/PhysRevB.66.064513
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
Andreev reflection tunneling spectroscopy on MgB2/PtIr point contacts have systematically been investigated. By fitting tunneling conductance to Blonder-Tinkham-Klapwijk theory, s-wave superconducting gaps were obtained. The distribution of the obtained gaps unequivocally shows two groups: one centered at 9.8 meV and the other peaked at 2.8 meV with a gap ratio of 3.5. For two typical gaps Delta(1)=1.92 meV and Delta(2)=3.45 meV their temperature-dependent behavior display that Delta(1)(T) unambiguously persists to the bulk T-c, 39 K, and Delta(2)(T) closes at 33 K. The results support multigap scenarios; in addition our experiments yield a much higher value of the large gap than the previous reports and theoretical predictions, indicating there may exist even stronger electron-phonon coupling in MgB2.
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页码：1 / 5
页数：5
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