Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 5: Quantenpunkte und -dr
ähte: Transporteigensch. I
HL 5.12: Vortrag
Montag, 11. März 2002, 13:15–13:30, H17
Stark effect in colloidal nanocrystal quantum dots — •Michael Tews and Daniela Pfannkuche — Inst. Theor. Physik, Universität Hamburg, Jungiusstr. 9, 20355 D-Hamburg
In a scanning tunneling spectroscopy experiment on colloidal InAs nanocrystals the particle is subjected to a strong electric field. Accordingly, the Stark effect leads to a splitting of the degenerate 1Pe states. We have calculated this splitting within a particle-in-a-sphere model and found that it reveals a possible explanation for a recent experiment by Millo et al. [1] in which the wave functions of the nanocrystal were mapped.
In order to cross-check the competition between the Stark induced reordering of states and the occupation of levels due to Hund’s rule we have estimated the Coulomb interaction for a system of more than one electron in the 1P shell by first order perturbation theory. We could show that the Stark splitting, for some particular configuration, is partly compensated by the exchange energy.
[1] O. Millo, D. Katz, Y. Cao, and U. Banin, Phys. Rev. Lett. 86, 5751 (2001)