تقرير
Full-gap superconductivity robust against disorder in heavy-fermion CeCu2Si2
| العنوان: | Full-gap superconductivity robust against disorder in heavy-fermion CeCu2Si2 |
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| المؤلفون: | Takenaka, T., Mizukami, Y., Wilcox, J. A., Konczykowski, M., Seiro, S., Geibel, C., Tokiwa, Y., Kasahara, Y., Putzke, C., Matsuda, Y., Carrington, A., Shibauchi, T. |
| المصدر: | Phys. Rev. Lett. 119, 077001 (2017) |
| سنة النشر: | 2017 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons |
| الوصف: | A key aspect of unconventional pairing by the antiferromagnetic spin-fluctuation mechanism is that the superconducting energy gap must have opposite sign on different parts of the Fermi surface. Recent observations of non-nodal gap structure in the heavy-fermion superconductor CeCu$_2$Si$_2$ 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 CeCu$_2$Si$_2$. 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. Comment: 5 pages, 4 figures + Supplemental Material (1 page, 1 figure). Will appear in Phys. Rev. Lett |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevLett.119.077001 |
| URL الوصول: | http://arxiv.org/abs/1705.06075 |
| رقم الأكسشن: | edsarx.1705.06075 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevLett.119.077001 |
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