Agterberg D F, Shishidou T, O'Halloran J, Brydon P M R, Weinert M
Department of Physics, University of Wisconsin, Milwaukee, Wisconsin 53201, USA.
Department of Physics, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
Phys Rev Lett. 2017 Dec 29;119(26):267001. doi: 10.1103/PhysRevLett.119.267001. Epub 2017 Dec 28.
Monolayer FeSe exhibits the highest transition temperature among the iron based superconductors and appears to be fully gapped, seemingly consistent with s-wave superconductivity. Here, we develop a theory for the superconductivity based on coupling to fluctuations of checkerboard magnetic order (which has the same translation symmetry as the lattice). The electronic states are described by a symmetry based k·p-like theory and naturally account for the states observed by angle resolved photoemission spectroscopy. We show that a prediction of this theory is that the resultant superconducting state is a fully gapped, nodeless, d-wave state. This state, which would usually have nodes, stays nodeless because, as seen experimentally, the relevant spin-orbit coupling has an energy scale smaller than the superconducting gap.
单层FeSe在铁基超导体中展现出最高的转变温度，并且似乎是完全能隙化的，这看似与s波超导性相符。在此，我们基于与棋盘状磁序涨落的耦合（其具有与晶格相同的平移对称性）发展了一种超导理论。电子态由基于对称性的类k·p理论描述，自然地解释了角分辨光电子能谱所观测到的态。我们表明该理论的一个预测是，所得的超导态是一个完全能隙化、无节点的d波态。这个通常会有节点的态保持无节点，是因为如实验所见，相关的自旋轨道耦合的能量尺度小于超导能隙。
