Superconducting gap symmetry in the superconductor BaFe1.9Ni0.1As2

被引：7

作者：

Kuzmicheva, T. E. ^{[1
]}

Kuzmichev, S. A. ^{[1
,2
]}

Sadakov, A. V. ^{[1
]}

Gavrilkin, S. Yu. ^{[1
]}

Tsvetkov, A. Yu. ^{[1
]}

Lu, X. ^{[3
]}

Luo, H. ^{[3
]}

Vasiliev, A. N. ^{[2
,4
,5
]}

Pudalov, V. M. ^{[1
]}

Chen, Xiao-Jia ^{[6
]}

Abdel-Hafiez, Mahmoud ^{[5
,7
]}

机构：

[1] Russian Acad Sci, PN Lebedev Phys Inst, Moscow 119991, Russia

[2] Moscow MV Lomonosov State Univ, Fac Phys, Moscow 119991, Russia

[3] Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Inst Phys, Beijing 100190, Peoples R China

[4] Natl Res South Ural State Univ, Chelyabinsk 454080, Russia

[5] Natl Univ Sci & Technol MISiS, Moscow 119049, Russia

[6] Ctr High Pressure Sci & Technol Adv Res, Shanghai 201203, Peoples R China

[7] Ctr High Pressure Sci & Technol Adv Res, Beijing 100094, Peoples R China

来源：

PHYSICAL REVIEW B | 2018年 / 97卷 / 23期

基金：

俄罗斯科学基金会; 中国国家自然科学基金; 俄罗斯基础研究基金会;

关键词：

IRON-BASED SUPERCONDUCTORS; PHOTOEMISSION-SPECTROSCOPY; ANDREEV SCATTERING; JUNCTIONS; STATE; FESE;

D O I：

10.1103/PhysRevB.97.235106

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We report on the Andreev spectroscopy and specific heat of high-quality single crystals of BaFe1.9Ni0.1As2. The intrinsic multiple Andreev reflection spectroscopy reveals two anisotropic superconducting gaps Delta(L) approximate to 3.2-4.5 meV, Delta(S) approximate to 1.2-1.6 meV (the ranges correspond to the minimum and maximum value of the coupling energy in the k(x)k(y) plane). The 25%-30% anisotropy shows the absence of nodes in the superconducting gaps. Using a two-band model with s-wave-like gaps Delta(L) approximate to 3.2 meV and Delta(S) approximate to 1.6 meV, the temperature dependence of the electronic specific heat can be well described. A linear magnetic field dependence of the low-temperature specific heat offers further support of s-wave type of the order parameter. We find that a d-wave or single-gap BCS theory under the weak-coupling approach cannot describe our experiments.

引用

页数：10

共 82 条

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