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Non-universal transmission phase behaviour of a large quantum dot
Hermann Edlbauer1, Shintaro Takada1,2, Grégoire Roussely1
1Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France.
Nature Communications
|November 24, 2017
Summary
Researchers observed transmission phase shifts in large quantum dots, revealing both phase lapses and plateaus. Quantum dot deformation was shown to control these phenomena by altering electron state parity.
Area of Science:
- Quantum physics
- Condensed matter physics
- Mesoscopic physics
Background:
- Electron wave function phase modification occurs during coherent transmission through quantum dots.
- A characteristic phase shift of π is observed when scanning through Coulomb blockade resonance.
- Theoretical models predict transmission phase lapses or plateaus between resonances, dependent on quantum dot state parity.
Purpose of the Study:
- To experimentally investigate the elusive transmission phase behavior in large quantum dots hosting hundreds of electrons.
- To characterize the sequence of phase lapses and plateaus across multiple Coulomb blockade resonances.
- To understand the influence of quantum dot deformation on transmission phase dynamics.
Main Methods:
- Utilized an original two-path interferometer to measure transmission phase across a large quantum dot.
- Scanned the transmission phase across 14 successive Coulomb blockade resonances.
- Investigated the effect of quantum dot deformation on the observed phase phenomena.
Main Results:
- Successfully observed both transmission phase lapses and plateaus in a large quantum dot.
- Demonstrated that quantum dot deformation can alter the sequence of phase lapses and plateaus.
- Correlated these alterations with modifications in the parity of quantum dot states.
Conclusions:
- The study provides the first experimental observation of transmission phase lapses and plateaus in large quantum dots.
- Quantum dot deformation is identified as a key factor influencing transmission phase behavior through parity control.
- These findings represent a significant step towards a comprehensive understanding of quantum dot transmission phase physics.
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