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Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Localization-delocalization transition of indirect excitons in lateral electrostatic lattices
M Remeika1, J C Graves, A T Hammack
1Department of Physics, University of California at San Diego, La Jolla, California 92093-0319, USA.
Physical Review Letters
|June 13, 2009
Summary
Researchers observed a transition in indirect exciton transport within quantum wells. This transition, from localized to delocalized states, depends on lattice amplitude and exciton density, offering insights into exciton interactions.
Area of Science:
- Condensed matter physics
- Semiconductor physics
Background:
- Indirect excitons in coupled quantum wells are crucial for optoelectronic devices.
- Understanding exciton transport is key to controlling quantum phenomena.
Purpose of the Study:
- To investigate the transport properties of indirect excitons in GaAs/AlGaAs coupled quantum wells.
- To analyze the localization-delocalization transition in a linear lattice potential.
- To explore the role of exciton interactions and external potentials in transport phenomena.
Main Methods:
- Fabrication of GaAs/AlGaAs coupled quantum wells.
- Creation of linear lattices using laterally modulated gate voltage.
- Measurement of exciton transport across the lattice.
- Analysis of localization-delocalization transition with varying lattice amplitude and exciton density.
Main Results:
- Observed a clear localization-delocalization transition for indirect exciton transport.
- Transition occurred with decreasing lattice amplitude or increasing exciton density.
- Exciton interaction energy at the transition was found to be close to the lattice amplitude.
- Results align with a model of interaction-induced percolation through an external potential.
Conclusions:
- The study elucidates the mechanism of localization-delocalization transition in exciton transport.
- Exciton-exciton interactions play a critical role in percolation through external potentials.
- Lattice potentials can be utilized to estimate disorder strength and exciton interaction parameters.
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