Correlation satellites in optical and loss spectra

Pierluigi Cudazzo (1) , Lucia Reining (2)

1 Physics and Materials Science Research Unit
2 LSI - Laboratoire des Solides Irradiés - Irradiated Solids Laboratory

Coupling of excitations leads to intriguing effects on the spectra of materials. We propose a cumulant formulation for neutral electronic excitations which opens the way to describe effects such as double plasmon satellites or exciton-exciton coupling. Our approach starts from the GW + Bethe-Salpeter approximation to many-body perturbation theory which is based on a quasiparticle picture, and it adds coupling of excitations through a consistent inclusion of dynamically screened interactions. This requires one to consider scattering contributions that are usually neglected. The result is formulated in a way that highlights essential physics, that can be implemented as a postprocessing tool in first-principles codes, and that suggests which kind of materials and measurements should exhibit strong effects. This is illustrated using a model.

Domaines: Autre [cond-mat.other]

Pierluigi Cudazzo, Lucia Reining. Correlation satellites in optical and loss spectra. Physical Review Research, 2020, 2 (1), ⟨10.1103/PhysRevResearch.2.012032⟩. ⟨hal-03098565⟩