The coexistence of ferromagnetism and superconductivity in RuSr2GdCu2O8 was reported both from experiments (by Tallon et. al.) and first-principles calculations (by Pickett et. al.). Here we report that our first-principles full-potential linearized augmented plane wave (FLAPW) calculations, employing the precise crystal structure with structural distortions (i.e., RuO6 rotations) determined by neutron diffraction, demonstrate that antiferromagnetic ordering of the Ru moments is energetically favored over the previously proposed ferromagnetic ordering. Our results are consistent with recently performed magnetic neutron diffraction experiments (Lynn et. al). Ru t2g states, which are responsible for the magnetism, have only a very small interaction with Cu eg states, which results in a small exchange splitting of these states. The Fermi surface, characterized by strongly hybridized dpσ orbitals, has nesting features similar to those in the two-dimensional high Tc cuprate superconductors.
@article{arxiv.cond-mat/0010227,
title = {Magnetic and electronic structures of superconducting RuSr$_2$GdCu$_2$O$_8$},
author = {K. Nakamura and K. T. Park and A. J. Freeman and J. D. Jorgensen},
journal= {arXiv preprint arXiv:cond-mat/0010227},
year = {2009}
}
Comments
6 pages,6 figures, accepted for publication in Phys. Rev. B