Eliashberg Analysis of the Electrodynamic Response of Ba(Fe1−xRhx)2As2 Across the s± to s++ Order Parameter Transition

We report on the Eliashberg analysis of the electrodynamic response of Ba(Fe 1−x Rh x ) 2 As 2 single crystals across the disorder-induced s ± to s ++ transition. We previously experimentally identified the transition by its signature in the low temperature value of the penetration depth and observed a peculiar dependency of the critical temperature on disorder; subsequently, we proposed new hallmarks in the quasiparticle conductivity and surface impedance. Here we show that this whole set of data can be self consistently reproduced within an effective two-bands Eliashberg model with disorder treated beyond the Born approximation and with a small set of input parameters.