Physics Colloquium Series, Fall 2009 and beyond

Graphene, a single atomic layer of sp2-hybridized carbon atoms, has been the subject of intense scientific interest recently. Many of the most intriguing transport and optical properties of graphene relate directly to its two-dimensional (2D) electronic band structure, with its linear dispersion relation for the low-energy excitations near the K-point of the Brillion zone. Optical Spectroscopy provides a powerful tool to probe the structure of electronic excitations in graphene. In this talk I will review some of the basic properties of this novel material. I will then report several optical studies that I have been involved in the past year during my sabbatical at Columbia University. These studies investigate how the electronic structure of graphene can be altered through interlayer interaction as well as application of external electric fields in few-layer graphene.