Strong electron-phonon coupling of the Fe breathing mode of LaO_{1-x}F_xFeAs

The electron-phonon coupling of LaO${}_{1-x}$F${}_x$FeAs is re-investigated on the basis of density functional theory in local density approximation. The implications of the $(\pi ,\pi )$ nesting of the Fermi surfaces are carefully studied and found to lead to a non-standard electron-phonon coupling of the corresponding Fe in-plane breathing mode, which might make a strong contribution to the high superconducting transition temperature. The semi-metallic behavior of the undoped material is also further illuminated.