Electron-phonon coupling in 122 Fe pnictides analyzed by femtosecond time-resolved photoemission

Based on the results from femtosecond time-resolved photoemission, we compare three different methods for the determination of the electron-phonon coupling constant lambda in Eu- and Ba-based 122 FeAs compounds. We find good agreement between all three methods, which reveal a small lambda < 0.2. This makes simple electron-phonon-mediated superconductivity unlikely in these compounds.