Abstract
The existence of a neutron scattering resonance at a wave vector implies a sign change of the gap between two Fermi-surface regions separated by wave vector . For the Fe pnictides, a resonance has been observed for a wave vector which connects a hole Fermi surface around the point with an electron Fermi surface around the or points of the 1 Fe/unit cell Brillouin zone. Here we study the neutron scattering resonance for a five-orbital model within a random-phase approximation—BCS approximation. Our results show that both an isotropic sign-switched and an anisotropic extended -wave gap are consistent with the present data for near and that scattering at other momentum transfers can be useful in distinguishing between gap structures.
- Received 27 February 2009
DOI:https://doi.org/10.1103/PhysRevB.79.134520
©2009 American Physical Society