The massless Dirac particle moving at the speed of light has been a fascinating subject in relativistic quantum physics. Graphene, an isolated single atomic layer of graphite, now provides us an opportunity to investigate such exotic effects in low-energy condensed matter systems. The unique electronic band structure of the graphene lattice provides a linear dispersion relation where the Fermi velocity replaces the role of the speed of light in usual Dirac Fermion spectrum. In this presentation I will discuss experimental consequences of charged Dirac Fermion spectra in two representative low dimensional graphitic carbon systems: 1-dimensional carbon nanotubes and 2-dimensional graphene. The combination of semiconductor device fabrication techniques and the development of new methods of nanoscale material synthesis/manipulation enables us to investigate mesoscopic transport phenomena in these materials. Exotic quantum transport behavior, such as ballistic charge transport and unusual half-integer quantum Hall effect, both of which appear even at room temperature, are discovered in these materials. In addition, the promise of these materials for novel electronic device applications will be discussed.

Argonne Physics Division Colloquium Schedule