Transport properties of individual C60-molecules

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Understanding electron transport in molecular junctions is crucial for nanoscale electronics.
• Fullerenes, like C60, are promising molecular building blocks due to their unique electronic properties.

Purpose of the Study:

• Investigate the electrical and thermal transport properties of C60 molecules in contact with gold electrodes.
• Determine the optimal contact geometry and understand the underlying transport mechanisms.

Main Methods:

• Density-functional theory (DFT)-based calculations were employed.
• Analysis of molecular orbital hybridization and transmission spectra.

Main Results:

• Optimal contact involves binding to one or two C-atoms, promoting sp(2) to sp(3) hybridization.
• Transport is dominated by a hybridized unoccupied molecular orbital, splitting the lowest unoccupied molecular orbital triplet.
• Quantum interference between occupied and unoccupied orbitals suppresses conductance near the Fermi energy.

Conclusions:

• The conductance cannot be modeled by a single resonance; quantum interference is a key factor.
• A simple two-level model effectively explains the observed numerical findings and transport phenomena.