6 research outputs found
Phonon-assisted decoherence and tunneling in quantum dot molecules
We study the influence of the phonon environment on the electron dynamics in
a doped quantum dot molecule. A non-perturbative quantum kinetic theory based
on correlation expansion is used in order to describe both diagonal and
off-diagonal electron-phonon couplings representing real and virtual processes
with relevant acoustic phonons. We show that the relaxation is dominated by
phonon-assisted electron tunneling between constituent quantum dots and occurs
on a picosecond time scale. The dependence of the time evolution of the quantum
dot occupation probabilities on the energy mismatch between the quantum dots is
studied in detail.Comment: 4 pages, 2 figures, conference proceeding NOEKS10, to be published in
Phys. Stat. So
Theory of phonon-mediated relaxation in doped quantum dot molecules
A quantum dot molecule doped with a single electron in the presence of
diagonal and off-diagonal carrier-phonon couplings is studied by means of a
non-perturbative quantum kinetic theory. The interaction with acoustic phonons
by deformation potential and piezoelectric coupling is taken into account. We
show that the phonon-mediated relaxation is fast on a picosecond timescale and
is dominated by the usually neglected off-diagonal coupling to the lattice
degrees of freedom leading to phonon-assisted electron tunneling. We show that
in the parameter regime of current electrical and optical experiments, the
microscopic non-Markovian theory has to be employed.Comment: Final extended version, 5 pages, 4 figure