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Noise enhancement due to quantum coherence in coupled quantum dots
G Kiesslich1, E Schöll, T Brandes
1School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
Physical Review Letters
|February 1, 2008
Summary
Noise enhancement in quantum dot charge transport arises from quantum coherence and Coulomb blockade. This super-Poissonian charge transfer mechanism is sensitive to electron-phonon scattering, as shown by temperature dependence.
Area of Science:
- Quantum Physics
- Condensed Matter Physics
- Nanotechnology
Background:
- Quantum dots are nanoscale semiconductor particles with unique electronic properties.
- Charge transport in quantum dots is influenced by quantum mechanical effects and electrostatic interactions.
- Noise enhancement in charge transport is an intriguing phenomenon requiring further explanation.
Purpose of the Study:
- To explain the observed noise enhancement in charge transport through vertically coupled quantum dots.
- To elucidate the underlying mechanism involving quantum coherence and Coulomb blockade.
- To investigate the sensitivity of this mechanism to decoherence effects.
Main Methods:
- Theoretical modeling of charge transport in coupled quantum dots.
- Analysis of the interplay between quantum coherence and Coulomb blockade.
- Experimental measurements of charge transport and temperature dependence.
Main Results:
- The observed noise enhancement is explained by the combined effects of quantum coherence and strong Coulomb blockade.
- A novel mechanism for super-Poissonian charge transfer has been identified.
- The mechanism's strong sensitivity to decoherence, particularly from electron-phonon scattering, was demonstrated.
Conclusions:
- Quantum coherence and Coulomb blockade are key to understanding noise enhancement in quantum dot charge transport.
- Electron-phonon scattering-induced decoherence significantly impacts this charge transfer mechanism.
- The findings offer insights into controlling quantum transport in nanoscale devices.
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