A High-T-c Mechanism of Iron Pnictide Superconductivity due to Cooperation of Ferro-Orbital and Antiferromagnetic Fluctuations

作者：Yamada Takemi^*; Ishizuka Jun; Ono Yoshiaki

来源：Journal of the Physical Society of Japan, 2014, 83(4): 043704.

DOI：10.7566/JPSJ.83.043704

The electronic states and superconductivity in iron pnictides are studied on the basis of the 16 band d-p model which includes both the onsite Coulomb interaction between Fe d electrons and the intersite one between Fe d and pnictogen p electrons. The model well accounts for experimentally observed two fluctuations: the d-d interaction-enhanced antiferromagnetic (AFM) fluctuation and the d-p interaction-enhanced ferro-orbital (FO) fluctuation responsible for the C-66 elastic softening. The AFM fluctuation induces the repulsive pairing interaction for q similar to Q(AF) while the FO does the attractive one for q similar to 0 resulting in the s(+/-)-wave superconductivity where the two fluctuations cooperatively enhance the superconducting transition temperature T-c without any competition by virtue of the q-space segregation.

• 出版日期2014-4