We study the effects of intraband relaxation processes on optical manipulation protocols for $\mathit{sp}$ biexcitons hosted by CdTe disk-shaped quantum dots. The many-body states are calculated within the configuration interaction method starting from single-particle states given by the $k·p$ theory. The time-dependent occupations of relevant many-body states are extracted from the von Neumann-Lindblad equation for the density operator. We mainly investigate the generation of $\mathit{sp}$ biexcitons with two pulses of different polarizations ${\sigma }_{+}$ and ${\sigma }_{-}$. The fast hole relaxation processes prevent a high-fidelity controlled operation on $\mathit{sp}$ biexcitons and lead to the occupation of some transient states which can be optically probed. More importantly, the many-body structure of the transient states consists of two holes on the $s$ shell and antiparallel $\mathit{sp}$ triplet states for electrons. Our simulations show that these triplet states are more stable against decoherence as they can only be damaged through slow electron relaxation. The configuration mixing due to correlation effects is also discussed.

• Received 17 February 2014
• Revised 19 May 2014

DOI:https://doi.org/10.1103/PhysRevB.89.245415