Boltzmann subspaces in molecular junctions under a thermal bias.

Area of Science:

• Quantum electronics
• Molecular electronics
• Statistical mechanics

Background:

• Single molecule junctions allow studying molecules in non-equilibrium states.
• Thermal bias, imposed by electrodes at different temperatures, drives these systems.

Purpose of the Study:

• To investigate the emergence of an effective temperature in single molecules under thermal bias.
• To explore the conditions and implications of this effective temperature.

Main Methods:

• Utilized Pauli master equations for weak electrode-molecule coupling.
• Analyzed molecular Hamiltonian eigenstates and occupation probabilities.
• Modeled various junction scenarios, including electron-electron interactions and disorder.

Main Results:

• Demonstrated that molecules under thermal bias can achieve an approximate effective temperature at steady state.
• Observed clustering of molecular eigenstates into Boltzmann-distributed subspaces.
• Identified effective temperatures across different molecular junction models.

Conclusions:

• The concept of Boltzmann subspaces simplifies the understanding of transport in thermally biased molecular junctions.
• Provides guidelines for controlling the temperature of single-molecule electronic devices.
• Offers potential for reduced computational effort in simulations.