Orbital order, structural transition, and superconductivity in iron pnictides

Yuki Yanagi; Youichi Yamakawa; Naoko Adachi; Yoshiaki Ono

doi:10.1143/JPSJ.79.123707

Orbital order, structural transition, and superconductivity in iron pnictides

Yuki Yanagi, Youichi Yamakawa, Naoko Adachi, Yoshiaki Ono

Research output: Contribution to journal › Article › peer-review

48 Citations (Scopus)

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 T_Q which induces the tetragonal-orthorhombic structural transition at T_s - T_Q, together with the stripe-type antiferromagnetic order below T_N. Near the phase transitions, the system shows the s₊₊-wave superconductivity due to the orbital fluctuation for a large g case with T _q > T_N, while the s_±-wave due to the magnetic fluctuation for a small g case with T_Q ≤ T_N. The former case is consistent with the phase diagram of doped iron pnictides with T_s > T_N.

Original language	English
Article number	123707
Journal	journal of the physical society of japan
Volume	79
Issue number	12
DOIs	https://doi.org/10.1143/JPSJ.79.123707
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)

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10.1143/JPSJ.79.123707

Cite this

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title = "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 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.",

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T1 - Orbital order, structural transition, and superconductivity in iron pnictides

AU - Yanagi, Yuki

AU - Yamakawa, Youichi

AU - Adachi, Naoko

AU - Ono, Yoshiaki

PY - 2010/12

Y1 - 2010/12

N2 - 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.

AB - 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.

KW - Elastic softening

KW - Iron pnictides

KW - Orbital order

KW - Structural transition

KW - Superconductivity

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Orbital order, structural transition, and superconductivity in iron pnictides

Abstract

Keywords

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