Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 12: Quantum dots and wires: Optical properties I

HL 12.11: Vortrag

Montag, 26. März 2007, 17:30–17:45, H17

Exciton Aharonov-Bohm Effect and Emission Kinetics in Non-circular Nanorings — •Michal Grochol, Frank Grosse, and Roland Zimmermann — Institut für Physik der Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany

The exciton Aharonov-Bohm effect (X-ABE), an oscillatory component in the energy with magnetic field, has been studied recently in semiconductor quantum dots [1] and nanorings of type I and II [2]. The close relation between X-ABE and exciton persistent current induced by the optical excitation has been revealed. Moreover, the exciton emission kinetics, even though within a simplified model [3], has been investigated and limitations for the observability of X-ABE in circular nanorings have been found. Here we present calculations of the absorption and photoluminesce spectra, and wave functions for a non-circular nanoring having only one symmetry axis. It is shown that lowering the circular symmetry weakens X-ABE in general. However, if the asymmetry is small the observability of the X-ABE can be improved substantially accompanied by a change of the oscillation period compared to the circular case. This model represents a further step towards more realistic description of nanorings.

[1] M. Grochol, F. Grosse, and R. Zimmermann, Phys. Stat. Sol. (C) 3, 2518 (2006)

[2] M. Grochol, F. Grosse, and R. Zimmermann, Phys. Rev. B, 74, 115416 (2006).

[3] M. Grochol, F. Grosse, and R. Zimmermann, Phys. Stat. Sol (B) 243, 3834 (2006)