Magnetic resonance from the interplay of frustration and superconductivity

Motivated by iron-based superconductors, we develop a self-consistent electronic theory for the itinerant spin excitations in the regime of coexistence of the antiferromagnetic stripe order with wave vector Q1=(π,0) and s+− superconductivity. The onset of superconductivity leads to the appearance of a magnetic resonance near the wave vector Q2=(0,π), where magnetic order is absent. This resonance is isotropic in spin space, unlike the excitations near Q1, where the magnetic Goldstone mode resides. We discuss several features which can be observed experimentally.     «

Motivated by iron-based superconductors, we develop a self-consistent electronic theory for the itinerant spin excitations in the regime of coexistence of the antiferromagnetic stripe order with wave vector Q1=(π,0) and s+− superconductivity. The onset of superconductivity leads to the appearance of a magnetic resonance near the wave vector Q2=(0,π), where magnetic order is absent. This resonance is isotropic in spin space, unlike the excitations near Q1, where the magnetic Goldstone mode reside...     »