Investigating the role of anion polarizability in Fe-based superconductors via light-matter interaction

The polarizability of nearby ions may have a significant impact on electron interactions in solids, but only limited experimental data are available to support this picture. In this work, using a highly simplified description of the prototypical FeAs superconducting layer, we show how external optical excitation of the As $4p\text{−}5s$ splitting can lead to a significant modulation of the polarization-mediated effective interactions between carriers. Our results suggest that even perturbative external fields, approximately 2 orders of magnitude smaller than the internal field generated by charge carriers, might enable the exploration of the role of the anion's polarizability in determining the correlated physics, although more detailed modeling is needed to decide the optimal ways to achieve this.