Comment on "Orbital Order, Structural Transition and Superconductivity in Iron Pnictides" [arXiv:1010.0129] by Yanagi et al

Abstract

In contrast to the claim by Yanagi et al. in Ref. [1], the development of orbital fluctuations at $q ~ 0$ due to the "orthorhombic phonon" is unable to explain the high-Tc superconductivity in iron pnictides. The reason is that the orthorhombic-phonon is acoustic with the energy $\omega_q \propto q$, although the authors in Ref. [1] treated it as optical phonon ($\omega_o=0.02 eV$) inconsistently.