Charged excitons and biexcitons in laterally coupled (In,Ga)As quantum dots

We present results of atomistic empirical pseudopotential calculations and configuration interaction for excitons, positive and negative trions (X(+/-)), positive and negative quartons (X(2 +/-)), and biexcitons. The structures investigated are laterally aligned InGaAs quantum dot molecules embedded in GaAs under a lateral electric field. The rather simple energetic of excitons becomes more complex in the case of charged quasiparticles but remains tractable. The negative trion spectrum shows four anticrossings in the presently available range of fields while the positive trion shows two. The magnitude of the anticrossings reveals many-body effects in the carrier tunneling process that should be experimentally accessible.