Spin excitations in RbFe2As2

The nematic order in iron-based superconductors breaks the rotational symmetry of the lattice and is important for understanding the superconductivity. It has been shown that the low-energy spin excitations may be significantly affected by the nematic order. While in most cases the nematic direction in iron-based sueprconductors is along the (pi,0) direction, there are increasing evidences that there is an nematic order in RbFe2As2, whose direction is (pi,pi). Understanding this new type of nematicity is thus important to further investigating the origin of the nematic order and its interplay with the spin system and superconductivity. We thus propose to study the spin excitations in RbFe2As2 in details.