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arXiv · 1305.4108

Doping dependence of the spin excitations in Fe-based superconductors Fe1+yTe1-xSex

A. D. Christianson·M. D. Lumsden·K. Marty·C. H. Wang·S. Calder·D. L. Abernathy·M. B. Stone·H. A. Mook·M. A. McGuire·A. S. Sefat·B. C. Sales·D. Mandrus·E. A. Goremychkin
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Abstract

The Fe1+yTe1-xSex series of materials is one of the prototype families of Fe-based superconductors. To provide further insight into these materials we present systematic inelastic neutron scattering measurements of the low energy spin excitations for x=0.27, 0.36, 0.40, 0.49. These measurements show an evolution of incommensurate spin excitations towards the (1/2 1/2 0) wave vector with doping. Concentrations (x=0.40 and 0.49) which exhibit the most robust superconducting properties have spin excitations closest to (1/2 1/2 0) and also exhibit a strong spin resonance in the spin excitation spectrum below Tc. The resonance signal appears to be closer to (1/2 1/2 0) than the underlying spin excitations. We discuss the possible relationship between superconductivity and spin excitations at the (1/2 1/2 0) wave vector and the role that interstitial Fe may play.

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A. D. Christianson, M. D. Lumsden, K. Marty, C. H. Wang, S. Calder, D. L. Abernathy, M. B. Stone, H. A. Mook, M. A. McGuire, A. S. Sefat, B. C. Sales, D. Mandrus, E. A. Goremychkin. 2013-05-17. Doping dependence of the spin excitations in Fe-based superconductors Fe1+yTe1-xSex. https://doi.org/10.1103/physrevb.87.224410

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