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HL: Halbleiterphysik

HL 48: Quantenpunke und -dr
ähte: Transporteigenschaften III

HL 48.5: Vortrag

Donnerstag, 27. März 2003, 16:15–16:30, BEY/81

Level anticrossings in quantum dots probed by single electron tunneling — •Jens Könemann¹, Maik Krüger¹, Duncan Maude², Andreas Waag³, and Rolf J. Haug¹ — ¹Institut für Festkörperphysik, Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany — ²High Magnetic Field Laboratory, CNRS, 25 Avenue des Martyrs, BP 166, 38042 Grenoble cedex 9, France — ³Universität Ulm, Abteilung Halbleiterphysik, Albert-Einstein-Allee 45, 89069 Ulm

We have studied the single-particle spectrum of a single localized state in a vertical resonant tunneling structure in high magnetic fields up to 28 T. At low magnetic fields the eletronic levels were not equally-spaced as to be expected for a harmonic confinement, but lifting of the degeneracy of orbital states is observed. Our measurements of the spectrum are in agreement to theoretical predictions considering an anisotropic confinement potential of our localized state.

At high magnetic fields beyond 12 T the traces of the electronic levels follow parallel lines with an equal spacing and a constant slope in the magnetic field, while a linear Zeeman splitting with g-factors of |g^*|≈ 0.25 is observed.

In the intermediate field range between 4 T and 12 T strong anti-crossings of the electronic levels are observed.