Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 7: Quantum dots and wires: Optical properties I
HL 7.2: Vortrag
Montag, 27. März 2006, 10:30–10:45, POT 151
Impact of Piezoelectricity on Shape and Order of Wavefunctions in Uncapped InAs/GaAs Quantum Dots — •Andrei Schliwa1, Theophilos Maltezopoulos2, Markus Morgenstern3, Roland Wiesendanger2, and Dieter Bimberg1 — 1Institut für Festkörperphysik, Technische Universität*Berlin — 2Institute of Applied Physics, University of Hamburg — 3II. Inst. of Physics B, RWTH Aachen University
Recently it became possible to map the shape of electron
wave-functions in uncapped InAs/GaAs quantum dots (QDs) by
using scanning tunneling spectroscopy (STS) [1].
These measurement revealed an anomalous order of the
single particle states in most of the investigated QDs
which triggered the here presented theoretical
investigations based on the
eight-band-k·p model.
The outer shape of the model-QD is specified by using the
morphological data, recorded as a byproduct of the STS-method,
whilst the composition profile has been treated as variable.
All of the measured QDs are elongated in [110] direction with a larger
in-plane anisotropy-ratio at the QD-apex than at the bottom.
This alone however is not sufficient to explain the observed
wavefunction order. It requires the inclusion of the strain induced piezoelectric field
to amplify the already present confinement anisotropy to finally obtain the anomalous
order of the electron orbitals in the simulation.
[1] Maltezopoulos T., Bolz A., Meyer C., Heyn C., Hansen W., Morgenstern M.,
Wiesendanger R., Phys. Rev. Lett. 91, p.196804 (2003)