Adroja D T, Blundell S J, Lang F, Luo H, Wang Z-C, Cao G-H
ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX, United Kingdom.
Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa.
J Phys Condens Matter. 2020 Aug 3;32(43). doi: 10.1088/1361-648X/aba28f.
We report inelastic neutron scattering (INS) investigations on the bilayer Fe-based superconductor CsCaFeAsFabove and below its superconducting transition temperature≈ 28.9 K to investigate the presence of a neutron spin resonance. This compound crystallises in a body-centred tetragonal lattice containing asymmetric double layers of FeAsseparated by insulating CaFlayers and is known to be highly anisotropic. Our INS study clearly reveals the presence of a neutron spin resonance that exhibits higher intensity at lower momentum transfer () at 5 K compared to 54 K, at an energy of 15 meV. The energyof the observed spin resonance is broadly consistent with the relationship= 4.9, but is slightly enhanced compared to the values observed in other Fe-based superconductors. We discuss the nature of the electron pairing symmetry by comparing the value ofwith that deduced from the total superconducting gap value integrated over the Fermi surface.
我们报道了对双层铁基超导体CsCaFeAsF在其超导转变温度（约28.9 K）上下进行的非弹性中子散射（INS）研究，以探究中子自旋共振的存在。该化合物结晶于体心四方晶格中，包含由绝缘Ca层分隔的不对称FeAs双层，并且已知具有高度各向异性。我们的INS研究清楚地揭示了中子自旋共振的存在，在5 K时，与54 K相比，该共振在较低动量转移（）下、能量为15 meV时表现出更高的强度。观察到的自旋共振能量与关系= 4.9大致一致，但与在其他铁基超导体中观察到的值相比略有增强。我们通过将的值与从费米面积分得到的总超导能隙值推导的值进行比较，来讨论电子配对对称性的本质。
