Full-Gap Superconductivity Robust against Disorder in Heavy-Fermion CeCu2Si2

被引：36

作者：

Takenaka, T. ^{[1
]}

Mizukami, Y. ^{[1
]}

Wilcox, J. A. ^{[2
]}

Konczykowski, M. ^{[3
]}

Seiro, S. ^{[4
,5
]}

Geibel, C. ^{[4
]}

Tokiwa, Y. ^{[6
,7
]}

Kasahara, Y. ^{[6
]}

Putzke, C. ^{[2
]}

Matsuda, Y. ^{[6
]}

Carrington, A. ^{[2
]}

Shibauchi, T. ^{[1
]}

机构：

[1] Univ Tokyo, Dept Adv Mat Sci, Kashiwa, Chiba 2778561, Japan

[2] Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England

[3] Univ Paris Saclay, CEA, CNRS, Ecole Polytech,Lab Solides Irradies, F-91128 Palaiseau, France

[4] Max Planck Inst Chem Phys Solids, D-01187 Dresden, Germany

[5] IFW Dresden, Inst Solid State Phys, Helmholtzstr 20, D-01069 Dresden, Germany

[6] Kyoto Univ, Dept Phys, Kyoto 6068502, Japan

[7] Augsburg Univ, Inst Phys, Ctr Elect Correlat & Magnetism, D-86159 Augsburg, Germany

来源：

PHYSICAL REVIEW LETTERS | 2017年 / 119卷 / 07期

基金：

英国工程与自然科学研究理事会; 日本学术振兴会;

关键词：

PENETRATION DEPTH; YBA2CU3O6.95;

D O I：

10.1103/PhysRevLett.119.077001

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

A key aspect of unconventional pairing by the antiferromagnetic spin-fluctuation mechanism is that the superconducting energy gap must have the opposite sign on different parts of the Fermi surface. Recent observations of non-nodal gap structure in the heavy-fermion superconductor CeCu2Si2 were then very surprising, given that this material has long been considered a prototypical example of a superconductor where the Cooper pairing is magnetically mediated. Here we present a study of the effect of controlled point defects, introduced by electron irradiation, on the temperature-dependent magnetic penetration depth. lambda (T) in CeCu2Si2. We find that the fully gapped state is robust against disorder, demonstrating that low-energy bound states, expected for sign-changing gap structures, are not induced by nonmagnetic impurities. This provides bulk evidence for s(||)-wave superconductivity without sign reversal.

引用

页数：5