Objective
The main goal of the submitted Project is experimental studies of collective phenomena of interacting excitons in coupled double quantum wells and superlattices on the basis of specially designed AlGaAs/GaAs heterostructures. Interest to these systems is connected with the possibility of formation of spatially indirect (interwell) excitons with a controllable overlap of wave functions of spatially separated electrons and holes. Due to long recombination lifetimes of indirect excitons different collective phenomena are expected under variation of e-h overlap and interparticle distances such as phase transition to the Excitonic Charge Density Wave and exciton condensation at finite wave vector.
Within the frames of the Project the interwell-intrawell exciton crossover and change of the exciton binding energy in structures with different well and barrier widths will be studied as function of magnetic and electric field. The lifetimes, energy- and phase- relaxation times of corresponding exciton states will be determined under resonant and off-resonant laser excitation. The collective modes of the interwell excitons of high density and phase transition to the state of excitonic density wave will be investigated by means of inelastic light scattering and photoluminescence at low temperatures (down to 0.4 K) and high magnetic field (up to 20 T).
The following experimental tools will be used in investigations: CW and time-resolved photoluminescence, time-resolved pump-probe and differential transmission, photoluminescence excitation and photoconductivity spectroscopies, resonant inelastic light scattering and non-linear four-wave mixing spectroscopy.
It is expected that the investigations proposed will clarify the nature of Coulomb correlations in the bi-dimensional exciton system of high density and enable determination of the phase transition diagram in the case of interacting interwell excitons.
Topic(s)
Call for proposal
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38042 Grenoble
France