2009.06.16

222, Eigineering 2nd Bld, Hongo Campus

Prof. Thomas Pichler

   Facultly of Physics, University of Vienna 

Abstract:

The presentation will give an overview on our current research focus on the electronic properties of low dimensional quantum solids. These properties are strongly influenced by basic correlation effects. Archetypical examples of these systems are graphene, graphite and single wall carbon nanotubes (SWCNT) which are determined by the local arrangement of their sp2 hybridised carbon atoms, such that their character is either semi-metallic, insulating, miconducting or metallic. Examples of the recent work on how one can analyse these electronic properties using high energy spectroscopy (electron energy-loss, photoemission and x-ray absorption spectroscopy) as a probe will be presented. Special emphasis will be given to the influence of basic correlation effects and local field corrections on the electronic properties of graphene, graphite and SWCNT. The latter exhibit for metallic tubes a Luttinger liquid behavior. Special emphasis will be on the influence of the bundling/ debundling (van der Waals interaction) and the influence of  metallicity selected, i.e. purely metallic vs. purely semiconducting, SWCNT will be given. Furthermore, an overview on how to functionalize them in order to tailor their electronic structure will be given.  This includes examples for the three alternative doping routes, namely, substitution, intercalation and endohedral doping (e.g. By filling with fullerenes and metallocenes) as well as examples for the growth of defined innertubes from the different precursors via a thermal nanochemical reaction. In comparison to graphite intercalation compounds, the electronic structure of doped graphene will be unravelled. For metallic functionalized nanotubes doping induced changes will be discussed in the framework of a dimensionality crossover  which causes a change from a one-dimensional metal to a normal Fermi liquid. The detailed understanding of these fundamental electronic properties of functionalised graphite, SWCNT and graphene is key to their future success.

Schedule: 14:45 ~ 16:00  Tuesday  16th  June, 2009

Place: 222, Engineering 2nd Bld, Hongo Campus

Attached file: 21st open seminar.pdf