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arXiv · 1106.4552

Extended Hubbard model of superconductivity driven by charge fluctuations in iron-pnictides

Sen Zhou·G. Kotliar·Ziqiang Wang
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Abstract

We present a scenario for iron-pnictide superconductivity mediated by charge fluctuations that are strongly enhanced by Fe-As intersite electronic interactions. Deriving an eight-band extended Hubbard model including Fe 3$d$ and As 4$p$ orbitals for the LaOFeAs family, we show that charge fluctuations induced by $p$-$d$ charge transfer and As orbital polarization interactions in the Fe-pnictogen structure peak at wavevectors $(0, 0)$, and ($\pi$, 0) and ($\pi$, $\pi$) respectively. Intraorbital spin-singlet pairing attraction develops at these wavevectors and the solution of the linearized gap equation shows robust s-wave superconductivity with both $s_\pm$ and $s_{++}$ gap functions.

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Sen Zhou, G. Kotliar, Ziqiang Wang. 2011-06-22. Extended Hubbard model of superconductivity driven by charge fluctuations in iron-pnictides. https://doi.org/10.1103/physrevb.84.140505

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