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arXiv · 1309.4197

Universality of dispersive spin-resonance mode in superconducting BaFe2As2

C. H. Lee·P. Steffens·N. Qureshi·M. Nakajima·K. Kihou·A. Iyo·H. Eisaki·M. Braden
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Abstract

Spin fluctuations in superconducting BaFe2(As1-xPx)2 (x=0.34, Tc = 29.5 K) are studied using inelastic neutron scattering. Well-defined commensurate magnetic signals are observed at (π,0), which is consistent with the nesting vector of the Fermi surface. Antiferromagnetic (AFM) spin fluctuations in the normal state exhibit a three-dimensional character reminiscent of the AFM order in nondoped BaFe2As2. A clear spin gap is observed in the superconducting phase forming a peak whose energy is significantly dispersed along the c-axis. The bandwidth of dispersion becomes larger with approaching the AFM ordered phase universally in all superconducting BaFe2As2, indicating that the dispersive feature is attributed to three-dimensional AFM correlations. The results suggest a strong relationship between the magnetism and superconductivity.

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C. H. Lee, P. Steffens, N. Qureshi, M. Nakajima, K. Kihou, A. Iyo, H. Eisaki, M. Braden. 2013-09-17. Universality of dispersive spin-resonance mode in superconducting BaFe2As2. https://doi.org/10.1103/physrevlett.111.167002

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