1. Fully gapped d-wave superconductivity in CeCu2Si2
- Author
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Hirale S. Jeevan, W. Xie, Yongjun Zhang, Lin Jiao, Philipp Gegenwart, W. B. Jiang, Z. F. Weng, Jinglei Zhang, Michael Smidman, Huiqiu Yuan, Emilian M. Nica, Frank Steglich, G. M. Pang, Qimiao Si, Ye Chen, and Hanoh Lee
- Subjects
Physics ,Superconductivity ,Multidisciplinary ,Condensed matter physics ,Condensed Matter - Superconductivity ,London penetration depth ,FOS: Physical sciences ,02 engineering and technology ,Heavy fermion superconductor ,021001 nanoscience & nanotechnology ,Computer Science::Digital Libraries ,01 natural sciences ,Inelastic neutron scattering ,Symmetry (physics) ,Superfluidity ,Superconductivity (cond-mat.supr-con) ,Pairing ,Condensed Matter::Superconductivity ,0103 physical sciences ,Computer Science::Mathematical Software ,ddc:530 ,010306 general physics ,0210 nano-technology ,Penetration depth - Abstract
The nature of the pairing symmetry of the first heavy fermion superconductor CeCu$_2$Si$_2$ has recently become the subject of controversy. While CeCu$_2$Si$_2$ was generally believed to be a $d$-wave superconductor, recent low temperature specific heat measurements showed evidence for fully gapped superconductivity, contrary to the nodal behavior inferred from earlier results. Here we report London penetration depth measurements, which also reveal fully gapped behavior at very low temperatures. To explain these seemingly conflicting results, we propose a fully gapped $d+d$ band-mixing pairing state for CeCu$_2$Si$_2$, which yields very good fits to both the superfluid density and specific heat, as well as accounting for a sign change of the superconducting order parameter, as previously concluded from inelastic neutron scattering results., Comment: 9 pages, 6 figures including Supplemental material. Published version in PNAS available online ahead of print at http://www.pnas.org/content/early/2018/05/07/1720291115
- Published
- 2018