Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 5: Quantenpunkte und -dr
ähte: Transporteigensch. I
HL 5.13: Vortrag
Montag, 11. März 2002, 13:30–13:45, H17
Control of Dephasing and Phonon Emission in Double Quantum Dots — •Stefan Debald1, Tobias Brandes2 und Bernhard Kramer1 — 11. Institut für Theoretische Physik, Universität Hamburg — 2Department of Physics, University of Manchester Institute of Science and Technology (UMIST), UK
We investigate non-linear electron transport through coupled quantum dots embedded into a nano-size semiconductor slab. It is known that at low temperatures the dynamics of the double quantum dot is governed by spontaneous emission of acoustic phonons [1,2]. Therefore, the pecularities of slab vibrations induced by the mechanical confinement, e.g. phonon subband quantization and van Hove singularities in the DOS, should effect the transport properties.
We predict that phonon subband quantization can be detected in the current through double quantum dots. For particular values of the tunable dot level splitting Δ, piezo-electric or deformation potential scattering is either drastically reduced as compared to the bulk case, or strongly enhanced due to van Hove singularities in the DOS of the phonons. By tuning Δ, this can be used to either control dephasing in double dot qubits, or to strongly increase phonon emission into modes with characteristic angular distributions.
[1] T. Fujisawa, T. H. Oosterkamp, W. G. van der Wiel, B. W. Broer, R. Aguado, S. Tarucha, and L. P. Kouwenhoven, Science 282, 932 (1998).
[2] T. Brandes and B. Kramer, Phys. Rev. Lett. 83, 3021 (1999).