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HL: Fachverband Halbleiterphysik
HL 7: Quantum dots: Optical properties I
HL 7.8: Vortrag
Montag, 23. März 2009, 15:30–15:45, BEY 118
Effect of uniaxial stress on single particle states and fine structure splitting of excitons in InGaAs self-assembled quantum dots — •Ranber Singh and Gabriel Bester — Max Planck Institute for Solid State Research, Stuttgart, Germany
We investigate the effect of uniaxial stress on single particle states and fine structure splitting (FSS) of excitons in InGaAs self-assembled quantum dots by applying uniaxial stress along the [110] and [100] crystallographic directions using the empirical pseudopotential approach and configuration interaction. It is shown that the tuning of FSS in quantum dots is sensitive to the atomistic symmetry of the structures and the direction of applied stress. Related to the structure’s symmetry, is the appearance of crossings as well as anti-crossings of the bright exciton lines. For stresses along [100], the minimum FFS is at 0 MPa (40 MPa) in InAs/GaAs (In0.6Ga0.4As/GaAs) dots. For the stress along [110] direction, the minimum FFS is at -19 MPa (-40 MPa) in InAs/GaAs (In0.6Ga0.4As/GaAs) dots. The single particle energies of S, P electron and hole states increases linearly with the increase in stress. The P hole states tend to spilt under [110] stress, while P electron states show no significant splittings.