Many-body effects in the dynamic charge response of silver chloride

When a material is exposed to a perturbation such as light or an electron beam, charge is redistributed dynamically. This process is particularly important for many applications such as photovoltaics or photocatalysis, where migration of charge due to irradiation with light is a key phenomenon. In linear response, the induced charge is given by the polarizability. The macroscopic response is measured in spectroscopies such as optical absorption, but to describe the charge dynamics, all microscopic components of the polarizability are needed. In the present work, we calculate the full microscopic polarizability of silver chloride [1] including crystal local field and electron-hole interaction effects and, from this, the charge dynamics. In particular, we demonstrate the dramatic impact of bound excitons.

[1] A.Lorin, M.Gatti, L.Reining, F.Sottile, "First-principles study of excitons in the optical spectra of silver chloride" arXiv:2009.08699 [cond-mat.mtrl-sci]