Structural and electronic properties of C60 fullerene network self-assembled on metal-covered semiconductor surfaces

Using first-principles density functional theory calculations, we made an accurate structural characterization of the C-60 superstructures self-assembled on the Tl-adsorbed Si(111) and Ge(111) surfaces, which finds a good agreement with the recent scanning tunneling microscopy observations. Our band structure calculations revealed the semi-metallic character of the C-60/Tl/Si(111) system, while the C-60/Tl/Ge(111) system was found to show up the pronounced metallic character due to the cascade of the flat bands lying in the vicinity of the Fermi level. The latter is a fingerprint for strong correlation effects in the C-60/Tl/Ge(111) system, which makes it a promising object for studying electrical transport phenomena and opens the prospects for its application in the molecular-based electronic devices. We elucidated the details of the molecule-substrate and intermolecular interactions and discussed the character of a charge transfer in both systems.

Automated summary

The study found that the C-60/Tl/Si(111) system exhibits semi-metallic character, while the C-60/Tl/Ge(111) system demonstrates pronounced metallic character due to the presence of flat bands near the Fermi level. The latter system shows strong correlation effects and potential for studying electrical transport phenomena and application in molecular-based electronic devices.