Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4
Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4
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DOI：
10.7566/jpsj.86.093703
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发表时间：
2017-09-15
影响因子：
1.7
通讯作者：
Iyo, Akira
中科院分区：
文献类型：
--
作者：
Iida, Kazuki;Ishikado, Motoyuki;Iyo, Akira
采用中子非弹性散射（INS）测量和无规相近似（RPA）计算相结合的方法研究了新型铁基超导体CaKFe 4As 4的动态自旋磁化率.粉末INS测量表明，在Q（res）= 1.17（1）埃（-1）处的自旋共振，对应于四进制标记中的（pi，pi）嵌套波矢量，在Tc以下演化。自旋共振的特征能量E-res = 12.5meV，小于超导能隙的2倍（2 Δ）。自旋共振动力学磁化率的宽能量特征可以通过RPA计算来解释，其中考虑了不同费米表面上的不同超导能隙。我们的INS和PRA研究表明，在CaKFe_4As_4超导配对性质是s（+/-）对称性。
The dynamical spin susceptibility in the new-structure-type iron-based superconductor CaKFe4As4 was investigated by using a combination of inelastic neutron scattering (INS) measurements and random phase approximation (RPA) calculations. Powder INS measurements show that the spin resonance at Q(res) = 1.17(1) angstrom(-1), corresponding to the (pi,pi) nesting wave vector in tetragonal notation, evolves below T-c. The characteristic energy of the spin resonance E-res = 12.5meV is smaller than twice the size of the superconducting gap (2 Delta). The broad energy feature of the dynamical susceptibility of the spin resonance can be explained by the RPA calculations, in which the different superconducting gaps on different Fermi surfaces are taken into account. Our INS and PRA studies demonstrate that the superconducting pairing nature in CaKFe4As4 is the s(+/-) symmetry.