Mechanism for controlling the exciton fine structure in quantum dots using electric fields: Manipulation of exciton orientation and exchange splitting at the atomic scale
Garnett W. Bryant, Natalia Malkova, James S. Sims
We use atomistic tight-binding theory with a configuration interaction description of Coulomb and exchange effects to describe excitons in quantum dots in a vertical electric field. We show that field-induced manipulation of exciton orientation and phase produces a drastic reduction of fine structure splitting, an anticrossing, and a 90 degree rotation of polarization, similar to the observed anticrossing. An atomistic analysis is needed to explain how exciton reorientation modifies anisotropic exchance and fine structure splitting without significantly altering other splittings.