Gating Single Molecules with Counterions.

Area of Science:

• Surface Science
• Molecular Electronics
• Nanoscale Chemistry

Background:

• Rare-earth molecular complexes offer unique electronic properties.
• Controlling charge distribution at the atomic scale is crucial for molecular electronics.
• Understanding electrostatic interactions on metallic surfaces is key for device fabrication.

Purpose of the Study:

• To achieve atomic-scale gating of rare-earth molecular complexes.
• To visualize local charge redistribution within these complexes.
• To investigate the impact of gating on electronic properties and inter-complex interactions.

Main Methods:

• Fabrication of lanthanum-based molecular complexes on Au(111) surfaces.
• Atomic-scale electrostatic gating using additional counterions.
• Scanning tunneling spectroscopy and spectroscopic mapping at 5 K.
• Density functional theory (DFT) and analytical calculations.

Main Results:

• Demonstrated atomic-scale gating and visualization of charge distribution.
• Observed redistribution of charges and positive shift of frontier orbitals due to internal Stark effect.
• Confirmed complex polarizability through theoretical calculations.
• Showed that charge states are maintained in multi-complex clusters.

Conclusions:

• Atomic-scale electrostatic gating effectively controls charge distribution in rare-earth complexes.
• The internal Stark effect plays a significant role in modulating electronic properties.
• Findings enable the design of robust charged rare-earth complexes for solid-state applications.