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Updated: May 20, 2026
05:20
Characterization of Thermal Transport in One-dimensional Solid Materials
Published on: January 26, 2014
Vibrational cooling, heating, and instability in molecular conducting junctions: full counting statistics analysis
1Chemical Physics Theory Group, Department of Chemistry, University of Toronto, 80 Saint George St., Toronto, Ontario, Canada, M5S 3H6. dsegal@chem.utoronto.ca.
Physical Chemistry Chemical Physics : PCCP
|July 25, 2012
Summary
We investigated vibrational cooling, heating, and instability in molecular junctions. We found that junctions can become unstable at higher bias but may stabilize again at even higher voltages, a phenomenon termed reentrant behavior.
Area of Science:
- Molecular Electronics
- Quantum Transport
- Statistical Mechanics
Background:
- Molecular junctions enable electron transport control.
- Vibrational modes influence electronic properties and stability.
- Understanding current-induced effects is crucial for device design.
Purpose of the Study:
- Investigate current-induced vibrational cooling, heating, and instability.
- Analyze these phenomena in donor-acceptor rectifying molecular junctions.
- Explore the role of harmonic and anharmonic vibrational modes.
Main Methods:
- Utilized a full counting statistics approach.
- Employed a master equation to model electron-hole pair excitations coupled to vibrational modes.
- Calculated charge current and effective mode temperature using analytical expressions.
Main Results:
- Confirmed the charge and heat exchange fluctuation theorem in the steady-state limit.
- Observed bias-induced cooling at low voltage and heating at higher voltages.
- Identified instability regimes and a reentrant behavior where unstable junctions stabilize at high bias.
Conclusions:
- The study provides insights into the complex interplay between electrical bias, molecular vibrations, and junction stability.
- The observed reentrant behavior offers potential for designing more robust molecular electronic devices.
- The findings are applicable to both harmonic and anharmonic molecular systems coupled to thermal environments.
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