Magnetic Excitations of Undoped Iron Oxypnictides

TL;DR

This paper investigates the magnetic excitations in undoped iron oxypnictides using a 3D Heisenberg model, providing analytic dispersion forms and criteria to distinguish coupling regimes, with implications for neutron scattering experiments.

Contribution

It introduces an analytic approach to magnetic excitations in iron oxypnictides, highlighting the role of c-axis coupling and offering qualitative criteria for different coupling regimes.

Findings

Analytic spin wave dispersion forms derived

Magnetization reduction depends on c-axis coupling

Criteria to distinguish coupling regimes provided

Abstract

We study the magnetic excitations of undoped iron oxypnictides using a three-dimensional Heisenberg model with single-ion anisotropy. Analytic forms of the spin wave dispersion, velocities, and structure factor are given. Aside from quantitative comparisons which can be made to inelastic neutron scattering experiments, we also give qualitative criteria which can distinguish various regimes of coupling strength. The magnetization reduction due to quantum zero point fluctuations shows clear dependence on the c-axis coupling.