Radiative decay of bound electron pairs into unbound interacting electrons in 2D materials with two-band spectrum

Bound electron pairs (BEPs) arising due to peculiarities of the band structure of topologically nontrivial materials are of interest as charge and spin carriers with energies in the band gap. Moreover, being composite bosons, BEPs can also possess completely unusual collective properties. In this regard, of highest importance is the problem of their decay time. The processes of radiative decay of BEPs are studied, considering the electron-electron interaction in the final state, into which the BEPs decay. It is found that the decay time of singlet BEPs lies in the nanosecond range. The radiative decay of triplet BEPs is impossible.