Spin Dynamics of a J1-J2-K Model for the Paramagnetic Phase of Iron Pnictides

Details Spin Dynamics of a J1-J2-K Model for the Paramagnetic Phase of Iron Pnictides Spin Dynamics of a J1-J2-K Model for the Paramagnetic Phase of Iron Pnictides

2011-12-20

arxiv.org/abs/1112.4785v1

Physics

Condensed Matter

Strongly Correlated Electrons

11 pages, 8 figures

Scientific paper

We study the finite-temperature spin dynamics of the paramagnetic phase of iron pnictides within an antiferromagnetic J1-J2 Heisenberg model on a square lattice with a biquadratic coupling -K $(S_i \cdot S_j)^2$ between the nearest-neighbor spins. Our focus is on the paramagnetic phase in the parameter regime of this J1-J2-K model where the ground state is a (\pi,0) collinear antiferromagnet. We treat the biquadratic interaction via a Hubbard-Stratonovich decomposition, and study the resulting effective quadratic-coupling model using both modified spin wave and Schwinger boson mean-field theories; the results for the spin dynamics derived from the two methods are very similar. We show that the spectral weight of dynamical structure factor S(q,\omega) is peaked at ellipses in the momentum space at low excitation energies. With increasing energy, the elliptic features expand towards the zone boundary, and gradually split into two parts, forming a pattern around (\pi,\pi). Finally, the spectral weight is anisotropic, being larger along the major axis of the ellipse than along its minor axis. These characteristics of the dynamical structure factor are consistent with the recent measurements of the inelastic neutron scattering spectra on BaFe2As2 and SrFe2As2.

Affiliated with

Also associated with

No associations

Rating

Spin Dynamics of a J1-J2-K Model for the Paramagnetic Phase of Iron Pnictides does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Spin Dynamics of a J1-J2-K Model for the Paramagnetic Phase of Iron Pnictides, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spin Dynamics of a J1-J2-K Model for the Paramagnetic Phase of Iron Pnictides will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-58749