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Dynamical symmetry breaking in transport through molecules
Andrea Donarini1, Milena Grifoni, Klaus Richter
1Theoretische Physik, Universität Regensburg, Regensburg, Germany.
Physical Review Letters
|December 13, 2006
Summary
Charge transport in molecular transistors shows asymmetry due to vibrational and electronic interactions. This dynamical symmetry breaking in quasidegenerate states leads to unique current behavior.
Area of Science:
- Quantum electronics
- Molecular electronics
- Condensed matter physics
Background:
- Understanding charge transport in molecular single-electron transistors is crucial for nanoscale electronic devices.
- The interplay between molecular vibrations and electronic states significantly influences charge transport dynamics.
- Quasidegenerate vibrational eigenstates in molecules present unique properties for electronic applications.
Purpose of the Study:
- To investigate the influence of vibrational and electronic degrees of freedom on charge transport in molecular single-electron transistors.
- To analyze the impact of a thermal environment and lead coupling on charge transport.
- To explain the origin of current asymmetry in relation to gate voltage.
Main Methods:
- Theoretical analysis of charge transport across a molecular single-electron transistor.
- Focus on molecules with quasidegenerate vibrational eigenstates and non-degenerate anionic configurations.
- Modeling the combined effects of thermal environment, lead coupling, and tunneling events.
Main Results:
- Demonstration of dynamical symmetry breaking in quasidegenerate vibrational eigenstates.
- Observation of differing occupations in these eigenstates due to thermal environment and lead coupling.
- Identification of an imbalance in eigenstate occupations leading to current asymmetry.
Conclusions:
- The study reveals a mechanism for current asymmetry in molecular transistors based on dynamical symmetry breaking.
- This asymmetry arises from the distinct occupations of quasidegenerate vibrational eigenstates.
- The findings provide insights into controlling charge transport in molecular electronic devices.
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