Evidence for two-gap superconductivity in Ba0.55K0.45Fe2As2 from directional point-contact Andreev-reflection spectroscopy

被引：93

作者：

Szabo, P. ^{[1
]}

Pribulova, Z. ^{[1
]}

Pristas, G. ^{[1
]}

Bud'ko, S. L. ^{[2
]}

Canfield, P. C. ^{[2
]}

Samuely, P. ^{[1
]}

机构：

[1] Slovak Acad Sci, Inst Expt Phys, Ctr Low Temp Phys, SK-04001 Kosice, Slovakia

[2] Iowa State Univ, Ames Lab, Ames, IA 50011 USA

来源：

PHYSICAL REVIEW B | 2009年 / 79卷 / 01期

关键词：

barium compounds; high-temperature superconductors; iron compounds; point contacts; potassium compounds; reflectivity; superconducting energy gap; superconducting transition temperature; GAPS;

D O I：

10.1103/PhysRevB.79.012503

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Directional point-contact Andreev-reflection spectroscopy measurements on the Ba0.55K0.45Fe2As2 single crystals are presented. The spectra show significant differences when measured in the ab plane in comparison with those measured in the c direction of the crystal. In the latter case only a reduced point-contact conductance around zero bias has been revealed persisting well above T-c and probably related to the structural and magnetic transitions in the system. Within the ab plane two superconducting energy gaps are detected below T-c. Here a reduced conductance above T-c could also be found. The fits of the ab-plane data to the superconducting s-wave two-gap model indicate that the smaller gap has a size below the BCS value while the large gap reveals much higher coupling strength.

引用

页数：4

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