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 T q > 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.
Original language | English |
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Article number | 123707 |
Journal | journal of the physical society of japan |
Volume | 79 |
Issue number | 12 |
DOIs | |
Publication status | Published - 2010 Dec |
Externally published | Yes |
Keywords
- Elastic softening
- Iron pnictides
- Orbital order
- Structural transition
- Superconductivity
ASJC Scopus subject areas
- Physics and Astronomy(all)