Scattering mechanisms in graphene

Graphene is an exciting new condensed matter system, both for the opportunity to observe the physics associated with massless Dirac Fermions in the laboratory, and because of materials parameters which make it attractive for technological applications such as high-frequency transistors and conducting, transparent films. However, only very recently has there emerged a coherent understanding of the processes which govern the charge carrier mobilityand conductivity in graphene. I will discuss experiments performed on atomically-clean[l] graphene on SiO₂ in ultra-high vacuum to determine the charge carrier scattering rates from charged impurities[2], lattice defects[ 3], and phonons (graphene acoustic phonons and substrate polar optical phonons)[4], as well as their dependence on dielectric environment[5]. The experiments point out both the promise of the material as well as the technological challenges that lie ahead in realizing better graphene samples.