Abstract
We study spin-wave excitations in by the spin-wave theory. Starting from the five-orbital Hubbard model and the perturbation theory, we derive an effective isospin- model in the large Hubbard () limit. Based on the energy-band structure calculated from the first-principles method, we find that the effective model can be further reduced to the model containing a ferromagnetic nearest-neighbor (NN) Kitaev interaction () and a NN off-diagonal exchange interaction (). With the spin-wave theory, we find that the model can give magnetic excitations, which is consistent with recent neutron-scattering experiments.
- Received 6 February 2017
- Revised 11 May 2017
DOI:https://doi.org/10.1103/PhysRevB.96.115103
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