Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 40: Quantum dots and wires: Optical properties III

HL 40.3: Vortrag

Donnerstag, 30. März 2006, 11:30–11:45, POT 151

Exciton Aharonov-Bohm Effect in Type I and II 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 dependence on the magnetic field, in semiconductor nanorings presents an open question. Although theoretical studies on infinitely narrow nanorings [1] have predicted the x-ABE, more realistic calculations including the finite width of the rings [2] could not confirm these findings.

We present calculations of absorption spectra for realistic ring geometries and material parameters for type I and type II band alignments [3]. x-ABE oscillations are found in both types of structures. Their amplitudes are larger for type II nanorings and increase with decreasing the ring radius. In specific type II nanorings the hole position in the lowest optically active exciton state changes from the center of the ring to the outside by increasing the magnetic field. Possible strategies for observing experimentally the Aharonov-Bohm effect for excitons in semiconductor nanorings are proposed.
[1] L. G. G. V. D. da Silva, S. E. Ulloa, and T. V. Shahbazyan, B 72, 125327 (2005)
[2] J. Song and S. E. Ulloa, Phys. Rev. B 63, 125302 (2001)
[3] M. Grochol, F. Grosse, and R. Zimmermann, cond-mat/0511324