title: Spin waves in the (0, π) and (0, π, π) ordered SDW states of the t-t' Hubbard model: application to doped iron pnictides.
abstract: Spin waves in the (0, π) and (0, π, π) ordered spin-density-wave (SDW) states of the t-t' Hubbard model are investigated at finite doping. In the presence of small t', these composite ferro-antiferromagnetic (F-AF) states are found to be strongly stabilized at finite hole doping due to enhanced carrier-induced ferromagnetic spin couplings as in metallic ferromagnets. Anisotropic spin-wave velocities, a spin-wave energy scale of around 200 meV, reduced magnetic moment and rapid suppression of magnetic order with electron doping x (corresponding to F substitution of O atoms in LaO(1 - x)F(x)FeAs or Ni substitution of Fe atoms in BaFe(2 - x)Ni(x)As(2)) obtained in this model are in agreement with observed magnetic properties of doped iron pnictides.
authors.affiliation: Department of Physics, Indian Institute of Technology, Kanpur, India.
authors.forename: Nimisha
authors.initials: N
authors.lastname: Raghuvanshi
authors.forename: Avinash
authors.initials: A
authors.lastname: Singh