The ground state of an antiferromagnetic superconductor in the presence of a homogeneous magnetic field

The effect of a homogeneous magnetic field, H₀. on the ground state of an antiferromagnetic superconductor has been investigated. Assuming a one-dimensional like half-filled band, we have found a new state having gapless superconductivity and H₀-dependent order parameter. This state exists for H_Q/Δ₀>0.22 and when ∣Δ ? H_Q∣?H₀ < Δ + H_Q (H_Q is the staggered magnetic field, Δ is the superconducting order parameter and Δ₀ is Δ in the absence of H_Q and H₀).