Electronic structure and phonon spectrum of binary iron-based superconductor FeSe in both nonmagnetic and striped antiferromagnetic phases

摘要

Using first-principles calculations, we investigate electronic structure and phonon spectrum of binary iron-based superconductor FeSe in both tetragonal nonmagnetic (NM) phase and orthorhombic striped antiferromagnetic (SAF) phase. It is found that the softening of atomic vibration modes and main electron-phonon coupling contribution from low-frequency Eliashberg spectral function ~(α2)F(ω) in SAF phase of FeSe lead to the enhancement of electron-phonon coupling strength ~(λe)p and logarithmically average frequency ωln. However, the obtained superconducting ~(Tc) in SAF phase just increases up to 0.34 K, even though Coulomb pseudopotential μ is limited to zero. As a result, our magnetic phonons calculation still rules out phonon mediated superconductivity, although the electron-phonon coupling through the spin channel play an important role in FeSe.