Hamburg 2001 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 12: Quantenpunkte und -dr
ähte: Transporteigenschaften I
HL 12.9: Vortrag
Montag, 26. März 2001, 17:30–17:45, S9/10
Nonlinear electron transport in double quantum dots coupled to confined phonons — •Stefan Debald1, Tobias Brandes2, and Bernhard Kramer1 — 1Inst. Theor. Physik, Universität Hamburg, Jungiusstr. 9, 20355 D-Hamburg — 2Dep. of Physics, University of Manchester (UMIST), P.O. Box 88, Manchester M60 1QD, UK
We investigate the influence of electron-phonon interaction on the
nonlinear electron
transport through a double quantum dot in a free standing quantum
well. In (partly) free standing structures, electron transport through
double dots is suspected to show signatures of phonon confinement. We
assume that such structures represent phonon cavities. With such a
model we find by using a numerical approach a staircase-like
phonon DOS superimposed by Van-Hove singularities for different
cavity mode families.
Using a model by Brandes and Kramer [1] we also
calculate the
nonlinear inelastic electron current through a double dot at low
temperatures. Within this model the transport is mediated by
spontaneous emission of phonons. The current-voltage characteristic
depends on the orientation of the double dot with respect to the
geometry of the cavity. Moreover, it is possible to determine the
family of the emitted phonons by the dot orientation. We show that the
signatures of the confinement in the phonon DOS also show up in the
electronic transport. The characteristic separation of the
staircase-like features is determined by the cavity width. Therefore,
it should be possible to detect the predicted phonon confinement
effects in the electron current.
[1] T. Brandes and B. Kramer,
Phys. Rev. Lett. 83, 3021 (1999)