Exciton Auger-Meitner recombination from first-principles

Auger-Meitner recombination (AMR) is a significant non-radiative loss mechanism in many optoelectronic devices. In systems of reduced dimensions, where the enhanced Coulomb interaction gives rise to strongly bound excitons, the Coulomb interaction can also lead to rapid exciton-exciton annihilation even at low to moderate excitation densities. Here, we develop a first-principles method to study AMR in the exciton picture. We start with excitons computed from a GW plus Bethe-Salpeter equation approach and evaluate Auger-Meitner scattering matrix elements to lowest order. We demonstrate the first ab initio calculation of AMR rates in carbon nanotubes, obtaining Auger coefficients in good agreement with experiments. Our method builds upon prior work using a free-carrier approximation and/or model Hamiltonians to study AMR in low-dimensional materials, and provides insight into the microscopic origin of AMR in such systems.