Orbital Order, Structural Transition and Superconductivity in Iron Pnictides
Abstract
We investigate the 16-band d-p model for iron pnictide superconductors in the presence of the electron-phonon coupling g with the orthorhombic mode which is crucial for reproducing the recently observed ultrasonic softening. Within the RPA, we obtain the ferro-orbital order below TQ which induces the tetragonal-orthorhombic structural transition at Ts = TQ, together with the stripe-type antiferromagnetic order below TN. Near the phase transitions, the system shows the s++ wave superconductivity due to the orbital fluctuation for a large g case with TQ > TN, while the s+- wave due to the magnetic fluctuation for a small g case with TQ < TN. The former case is consistent with the phase diagram of doped iron pnictides with Ts > TN.
Cite
@article{arxiv.1010.0129,
title = {Orbital Order, Structural Transition and Superconductivity in Iron Pnictides},
author = {Yuki Yanagi and Youichi Yamakawa and Naoko Adachi and Yoshiaki Ōno},
journal= {arXiv preprint arXiv:1010.0129},
year = {2015}
}
Comments
5 pages, 5 figures, minor changes, published in J. Phys. Soc. Jpn