Auger decay of degenerate and bose-condensed excitons in Cu2O

We study the nonradiative Auger decay of excitons in Cu2O, in which two excitons scatter to an excited electron and hole. The exciton decay rate for the direct and the phonon-assisted processes is calculated from first principles; incorporating the band structure of the material leads to a relatively shorter lifetime of the tripler-state ortho excitons. We compare our results with the Auger decay rate extracted from data on highly degenerate tripler excitons and Base-condensed singlet excitons in Cu2O.