Light-Induced Subnanometric Modulation of a Single-Molecule Electron Source.

Area of Science:

• Quantum physics
• Materials science
• Molecular electronics

Background:

• Single-molecule electron sources, typically fullerenes (~1 nm), exhibit unusual emission patterns under constant electric fields.
• These patterns, like crosses or two-leaf shapes, have remained unexplained for over 70 years.

Purpose of the Study:

• To investigate the origin of peculiar electron emission patterns from single-molecule fullerene sources.
• To explore the effect of femtosecond light pulses on these emission patterns.
• To establish a link between emission patterns and molecular orbitals.

Main Methods:

• Utilized single-molecule electron sources made of fullerenes.
• Applied constant electric fields to drive electron emission.
• Illuminated the sources with femtosecond laser pulses.
• Performed theoretical simulations to analyze emission patterns.

Main Results:

• Observed significantly modulated emission patterns upon illumination with femtosecond light pulses.
• Simulations revealed that the emission patterns directly correspond to single-molecule molecular orbitals.
• Demonstrated that modulations in patterns arise from dynamic variations in molecular orbitals.

Conclusions:

• The long-standing mystery of fullerene electron emission patterns is solved, identifying them as molecular orbitals.
• Achieved precise, subnanometric optical modulation of electron emission by controlling molecular orbitals.
• Opens new avenues for advanced molecular electronic devices and nanoscale optical control.