Fullerenes and Carbon Nanotubes

Fullerenes are exciting materials with great potential for uses in nanotechnological applications. The simplest fullerene structure is the C60 molecule, which consists of 60 carbon atoms arranged in a spherical shell.  These fullerides are challenging systems because both the electron-electron and electron-phonon interactions are large in comparison with the electronic bandwidth of the material.  Mott-insulator transitions, superconductivity, magnetism are exciting properties resulting.

Our research has focused on mapping the electronic structure of K3C60.  In the future we are interested in extending this study to other dopants and interaction with substrate and investigate superconductivity and magnetism in different fullerides compounds.

For more information see our publication in Science 300, 303-307 (2003).

 

Carbon Nanotubes:  The properties of electrons become more and more exotic when progressing from the three-dimensional world into lower dimensions. The appeal in one-dimensional structures lies in a substantial change of the electronic properties mainly caused by correlation effects among electrons constrained in one direction. The lowering of dimensionality in physical systems brings about a wide variety of phenomena such as collective charge modes, collective spin modes, Peierls instabilities. As a consequence the single particle picture breaks down in describing the ground and excited states of the systems and one is pushed toward more sophisticated frameworks, e.g. Luttinger liquids, Luther-Emery liquids, Mott insulators, etc.

We are interested in studying the electronic properties of quasi 1D nanostructures.  Currently our focus is on multiwall carbon nanotubes, using angle integrated PES.  We are also interested in other one dimensional structure such as BN nanotube and other semiconducting quantum wires.

 

Scanning electron microscope images showing the top view and the side view of typical aligned multi-walled C nanotubes samples grown by our collaborators.

 

 

Angle-integrated spectrum of aligned multiwall carbon nanotubes.