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Nonequilibrium Green's function theory for nonadiabatic effects in quantum electron transport
Vincent F Kershaw1, Daniel S Kosov1
1College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia.
The Journal of Chemical Physics
|December 17, 2017
Summary
We developed a new theory for electric current in molecular junctions, incorporating nonadiabatic nuclear motion. This approach enhances accuracy by considering nuclear velocities and accelerations, improving transport calculations.
Area of Science:
- Theoretical Chemistry
- Condensed Matter Physics
- Quantum Transport
Background:
- Accurate calculation of electric current in molecular junctions is crucial for nanoelectronic device development.
- Existing transport theories often neglect the influence of nuclear motion on electronic transport.
Purpose of the Study:
- To develop a theoretical framework that incorporates nonadiabatic nuclear motion into the calculation of electric current in molecular junctions.
- To provide a more accurate description of electron transport phenomena at the molecular level.
Main Methods:
- Development of nonequilibrium Green's function-based transport theory.
- Separation of time scales using the Wigner representation.
- Perturbative expansion based on central time derivatives to compute nonadiabatic corrections.
Main Results:
- Analytic expressions for non-adiabatic electronic Green's functions up to second order.
- Green's functions depend on molecular geometry, nuclear velocities, and accelerations.
- An extended electric current formula accounting for non-adiabatic corrections.
Conclusions:
- The developed theory provides a more comprehensive understanding of electron transport in molecular junctions.
- The inclusion of nonadiabatic effects is essential for accurate modeling of molecular devices.
- The theory is validated through calculations on a model molecular junction.
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