Conductance Switching in an Organometallic Single-Electron Transistor Using Current-Constrained Reduced-Density...

Area of Science:

• Quantum Chemistry
• Molecular Electronics
• Condensed Matter Physics

Background:

• Previous low-voltage experimental analysis of binuclear organometallic complexes revealed Kondo resonance signatures.
• Understanding molecular conductance switching at finite bias is crucial for developing molecular electronic devices.

Purpose of the Study:

• To investigate the molecular conductance switching at finite bias in a binuclear organometallic complex and its cation.
• To explore the role of strong electronic correlation and multireferenced character in determining molecular conductance.
• To compare theoretical predictions with experimental findings beyond the low-bias Kondo regime.

Main Methods:

• Application of variational reduced density matrix theory to analyze the strongly multireferenced nature of the system.
• Utilizing newly developed current-constrained two-electron reduced density matrix theory for accurate conductance calculations.
• Comparison with uncorrelated one-electron reduced density matrix calculations using Hartree-Fock molecular orbitals.

Main Results:

• Both correlated and uncorrelated methods qualitatively predict higher molecular conductance for the cationic species.
• The cationic partner exhibits an inherently high density of states for low-lying excited states, explaining its enhanced conductance.
• Theoretical predictions show quantitative agreement with experimental data even beyond the Kondo regime.

Conclusions:

• The observed low-bias conductance trend is maintained at higher biases, validating the theoretical approaches.
• Strong electronic correlation plays a significant role, but even simpler methods capture the essential qualitative trends.
• Key physical markers responsible for the high conductance of the charged species have been identified.