We study the elementary excitations in 5d transition metal oxideSr2IrO4 by calculating the particle-hole Green's function within the random phase approximation on an antiferromagnetic ground state in the two-dimensional multi-orbital Hubbard model. The obtained magnetic excitations of bound states show a characteristic dispersion in consistent with the experiments. In addition, two new types of excitations are found due to the interplay between spin-orbit interaction and Hund's coupling: a magnetic excitation as a bound state, which has energy gap at the Γ point, and an exciton as a resonant mode in the continuum of electron-hole pair creation.
@article{arxiv.1312.2348,
title = {Interplay between Hund's coupling and spin-orbit interaction on elementary excitations in Sr2IrO4},
author = {Jun-ichi Igarashi and Tatsuya Nagao},
journal= {arXiv preprint arXiv:1312.2348},
year = {2014}
}
Comments
6 pages, 3 figures, Latex, final version, to be published in Journal of the Physical Society of Japan