Doping dependence of the spin excitations in the Fe-based superconductors Fe1+yTe1−xSex
/ Authors
A. Christianson, M. Lumsden, K. Marty, C. Wang, S. Calder, D. Abernathy, M. Stone, H. Mook, M. McGuire, A. Sefat
and 3 more authors
/ Abstract
(Dated: June 21, 2013) 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.
Journal: Physical Review B