Neutron spin resonance as a probe of Fermi surface nesting and superconducting gap symmetry in Ba0.67K0.33(Fe1-xCOx)2AS2

作者：Zhang, Rui; Wang, Weiyi; Maier, Thomas A.; Wang, Meng; Stone, Matthew B.; Chi, Songxue; Winn, Barry; Dai, Pengcheng^*

来源：Physical Review B, 2018, 98(6): 060502.

DOI：10.1103/PhysRevB.98.060502

• EXCITATIONS

We use inelastic neutron scattering to study the energy and wave-vector dependence of the superconductivity-induced resonance in hole-doped Ba0.67K0.33(Fe1-xCox)(2)AS(2) (x = 0 and 0.08 with T-c approximate to 37 and 28 K, respectively). In previous work on electron-doped Ba(Fe0.963Ni0.037)(2)AS(2) (T-N = 26 K and T-c = 17 K), the resonance is found to peak sharply at the antiferromagnetic (AF) ordering wave vector Q(AF) along the longitudinal direction, but disperses upwards away from Q(AF) along the transverse direction [Kim et al., Phys. Rev. Lett. 110, 177002 (2013)]. For hole-doped x = 0 and 0.08 without AF order, we find that the resonance displays a ringlike upward dispersion away from Q(AF) along both the longitudinal and transverse directions. By comparing these results with calculations using the random phase approximation, we conclude that the dispersive resonance is a direct signature of isotropic superconducting gaps arising from nested hole-electron Fermi surfaces.

• 出版日期2018-8-30
• 单位中山大学