Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 5: Optical Properties I

HL 5.3: Talk

Monday, March 18, 2024, 10:00–10:15, EW 561

Interplay between excitons and lattice vibrations in the optical properties of monolayer boron nitride — •Giovanni Marini, Matteo Calandra, and Pierluigi Cudazzo — University of Trento, Department of Physics, Via Sommarive 14 Povo(TN)

Monolayer hexagonal boron nitride exhibits a complex optical response, the full understanding of which remains elusive. The photoluminescence spectrum is enriched with satellite features that hint at the existence of substantial couplings between excitons and phonons whose nature is completely unknown. Being photoluminescence experiments always performed in presence of a substrate, the knowledge of the basic properties of the isolated ideal layer constitutes fundamental reference for the interpretation of the experiments and allows disentangling the effect of the substrate. Here, through a cumulant expansion of the charge response function developed in the framework of many body perturbation theory, we performed a first principles study of the exciton-phonon coupling in monolayer boron nitride. Our results allows to identify the different exciton-phonon scattering channels and their effect on the optical properties of this system providing important insights about recent photoluminescence experiments.

Keywords: Exciton-phonon coupling; Photoluminescence; Absorption; Ab-initio simulations; Cumulant expansion