Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Phys Rev Lett. 2018 May 25;120(21):217001. doi: 10.1103/PhysRevLett.120.217001.
Recent observations of two nodeless gaps in superconducting CeCu_{2}Si_{2} have raised intensive debates on its exact gap symmetry, while a satisfactory theoretical basis is still lacking. Here we propose a phenomenological approach to calculate the superconducting gap functions, taking into consideration both the realistic Fermi surface topology and the intra- and interband quantum critical scatterings. Our calculations yield a nodeless s^{±}-wave solution in the presence of strong interband pairing interaction, in good agreement with experiments. This provides a possible basis for understanding the superconducting gap symmetry of CeCu_{2}Si_{2} at ambient pressure and indicates the potential importance of multiple Fermi surfaces and interband pairing interaction in understanding heavy fermion superconductivity.
最近在超导 CeCu2Si2 中观察到两个无节点间隙，这引发了关于其精确能隙对称性的激烈争论，而一个令人满意的理论基础仍然缺乏。在这里，我们提出了一种唯象方法来计算超导能隙函数，同时考虑了实际的费米面拓扑和 intra- 和 interband 量子临界散射。我们的计算在存在强 interband 配对相互作用的情况下得出了一个无节点 s^{±}-波解，与实验结果非常吻合。这为理解常压下 CeCu2Si2 的超导能隙对称性提供了一个可能的基础，并表明了多费米面和 interband 配对相互作用在理解重费米子超导电性方面的重要性。
