Neutron scattering study on NaFe1-xCoxAs
|Date/Time:||Thursday, 21 Aug 2014 - Thursday, 21 Aug 2014|
|Location:||PHYSICS Hall Room 3|
|Channel:||Condensed Matter Physics|
Since the discovery of iron superconductors, the (Ba,Sr,Ca)Fe2As2 ("122") family especially electron doped side has been subjected to heavily study byneutron scattering. One of the pronounced features generally observed in bulk superconducting compositions is a broad resonance along antiferrromagnetic order wave vector. The resonance energy linearly scales with Tc. However, our neutron study shows that Co-doped NaFeAs system exhibits complexity, distinguishing itself from "122" system. We observed a sharp resonance in the electron-overdope regime, providing strong evidence for S+_ pairing symmetry in pnictide superconductors. In the underdoped regime, we find double resonances at commensurate wave vector, demonstrating the multi-orbital nature of pnictides. Our finding further suggests that the resonance energy and Tc may not be simply correlated in multiband
superconductors such as iron pnictides.