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HL: Fachverband Halbleiterphysik

HL 58: Quantum Dots: Optical Properties IV

HL 58.6: Vortrag

Mittwoch, 22. März 2017, 16:45–17:00, POT 151

Inversion of permanent exciton dipole moment in self-assembled In(Ga)As quantum dots by nonlinear piezoelectricity — Johannes Aberl¹, •Petr Klenovsky^2,3, Johannes S. Wildmann¹, Javier Martin-Sanchez¹, Thomas Fromherz¹, Eugenio Zallo^4,5, Josef Humlicek^2,3, Armando Rastelli¹, and Rinaldo Trotta¹ — ¹Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, A-4040 Linz, Austria — ²Department of Condensed Matter Physics, Masaryk University, Kotlářská, CZ-61137 Brno, Czech Republic — ³Central European Institute of Technology, Masaryk University, Kamenice 753/5, CZ-62500 Brno, Czech Republic — ⁴Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstraße 20, D-01069 Dresden, Germany — ⁵Paul-Drude-Institut für Festkörperelektronik, Hausvogteilplatz 5-7, 10117 Berlin, Germany

We show tuning of the electric dipole moment of excitons confined in self-assembled In(Ga)As quantum dots by anisotropic biaxial stress up to complete erasure of its magnitude and inversion of its sign. We attribute this effect to the piezoelectricity due to applied stress, the magnitude of which we estimate using a simple model based on the piezotronic effect. Self-consistent k^→.p^→ calculations reveal that the strain-induced changes of the dipole moment in our QDs that we observe can be only accounted for by the nonlinear piezoelectric effect, the importance of which in QD-physics has been theoretically recognized but it proved to be difficult to single out experimentally.