  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.
