Rearrangement collision theory of phonon-driven exciton dissociation

Journal article

Understanding the processes governing the dissociation of excitons to free charge carriers in semiconductors and insulators is of central importance for photovoltaic applications. Dyson's S-matrix formalism provides a framework for computing scattering rates between quasiparticle states derived from the same underlying Hamiltonian, often reducing to familiar Fermi's "golden rule"like expressions at first order. By presenting a rigorous formalism for multichannel scattering, we extend this approach to describe scattering between composite quasiparticles and, in particular, the process of exciton dissociation mediated by the electron-phonon interaction. Subsequently, we derive rigorous expressions for the exciton dissociation rate, a key quantity of interest in optoelectronic materials, which enforce correct energy conservation and may be readily used in ab initio calculations. We apply our formalism to a three-dimensional model system to compare temperature-dependent exciton rates obtained for different scattering channels.

Authors: Coveney, CJN; Haber, JB; Alvertis, AM; Neaton, JB; Filip, MR

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review B
• Volume: 110
• Issue: 5
• Article number: 054307
• Publication date: 2024-08-12
• Acceptance date: 2024-07-10
• DOI: 10.1103/physrevb.110.054307
• EISSN: 2469-9969
• ISSN: 2469-9950
• Language: English
• Keywords: electron-phonon coupling; excitons; first-principles calculations; lattice dynamics; quasiparticles and collective excitations