Optical signatures of valence-band mixing in positive trion recombination spectra of double quantum dots

Abstract

We consider optical signatures of valence band mixing in positive trion and exciton complexes in vertically stacked InGaAs quantum dots. We use the configuration interaction method and an axially symmetric four-band Luttinger-Kohn Hamiltonian (KL) that allows for heavy-hole and light-hole band mixing due to spin-orbit interaction. A scalar effective hole mass model is also included for comparison. We found essential differences (i.e., different recombination patterns) between the KL and separated-bands model spectra. In the weak-coupling regime for KL model, we obtained a good agreement with experimentally observed X patterns in contrast to the scalar effective mass model.