Dispersion of neutron spin resonance in Ba(Fe1-yCry)2(As1-xPx)2

Spin resonance has been observed in almost all iron-based superconductors, while its origin is still unclear. In our recent studies, we found that in CaKFe4As4, where the crystal structure has an unique Fe-As bilayer, the spin resonance degenerates to odd and even modes with sinusoidal and cosinoidal L-modulations. This resonance can be also considered as a magnon-like excitation, and it also could happen even in the d-wave paring system CeCoIn5 under strong coupling. Here we propose to study the BaFe2(As,P)2 system and 3% Cr doping Ba(Fe1-yCry)2(As1-xPx)2, who has a very similar structure with CaKFe4As4, and strong L-modulation or dispersion of the spin resonance. By comparing CaKFe4As4 system with different gap modulation and strong spin resonance, we can further understand the origin of the neutron spin resonance mode.