Tuning of the valence band mixing of excitons confined in GaAs/AlGaAs quantum dots via piezoelectric-induced anisotropic strain

J. D. Plumhof , R. Trotta , V. Krapek , E. Zallo , Paola Atkinson (1) , S. Kumar , A. Rastelli , O. G. Schmidt

1 INSP - Institut des Nanosciences de Paris

This work presents an experimental method to tune the degree of heavy-hole (HH) and light-hole (LH) mixing of the ground state of quantum dots (QDs). A ferroelectric crystal is used to apply reversible anisotropic biaxial stress to thin nanomembranes, containing GaAs/AlGaAs QDs. The stress-induced modification of the QD anisotropy leads to a change of the relative intensity of the two emission lines produced by the recombination of neutral bright excitonic states. Such a change is ascribed to a variation of the degree of HH-LH mixing. At the same time the modified anisotropy produces a change of the excitonic fine structure splitting (FSS). Model calculations provide a qualitative insight into the relation between strain, HH-LH mixing, and the FSS in epitaxial GaAs/AlGaAs QDs. DOI: 10.1103/PhysRevB.87.075311

Domaines: Matière Condensée [cond-mat]

J. D. Plumhof, R. Trotta, V. Krapek, E. Zallo, Paola Atkinson, et al.. Tuning of the valence band mixing of excitons confined in GaAs/AlGaAs quantum dots via piezoelectric-induced anisotropic strain. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2013, 87 (7), pp.075311. ⟨10.1103/PhysRevB.87.075311⟩. ⟨hal-01240518⟩