Colloquium on June 7, 2010

Philip Kim
Columbia University

Relativistic quantum physics at the tip of your pencil: pseudo spins in graphene

Carbon based graphitic nanomaterials have been provided us opportunities to explore fundamental transport phenomena in low-energy condensed matter systems to reveal interesting analogy to the relativistic quantum mechanics. The unique electronic band structure of graphene lattice yields a linear energy dispersion relation where the Fermi velocity replaces the role of the speed of light and pseudo spin degree of freedom for the orbital wavefunction replaces the role of real spin in usual Dirac Fermion spectrum. In this presentation we will discuss experimental consequence of charged Dirac Fermion spectrum with pseudo spin structure in two representative low dimensional graphitic carbon systems: 1-dimensional carbon nanotubes and 2-dimensional graphene. Combined with semiconductor device fabrication techniques and the development of new methods of nanoscaled material synthesis/manipulation enables us to investigate mesoscopic transport phenomena in these materials. The exotic quantum transport behavior discovered in these materials, such as ballistic charge transport, unusual half-integer quantum Hall effect, electron wave Fabry-Perot intereference all of which appear even at room temperature.