The recent development of convenient techniques for producing experimentally viable samples of graphene has aroused tremendous interest in the condensed matter community. Among the fundamental questions related to graphene physics is its electronic properties, and how they

are modified in the presence of many-body interactions. In recent angle-resolved photoemission (ARPES) experiments, the quasi-relativistic

electron band structure of graphene was directly observed showing a strong kink at 200 meV below the Fermi level. On the other hand, Raman scattering experiments revealed an unconventional density dependence of the long-wavelength phonon energy at the G point. In light of these interesting developments, I will discuss how many-body effects due to electron-electron and electron-phonon interactions significantly modify the electronic properties of graphene, giving rise to the above-mentioned features in experiments. In particular, I will address the cardinal question in graphene physics whether or not the conventional Fermi liquid picture holds for graphene, and if so, how the electron and phonon properties are renormalized by many-body interactions.

Refs:

1. S. Das Sarma, E.H. Hwang, and W.-K. Tse, PRB 75 121406(R) (2007).

2. W.-K. Tse and S. Das Sarma, PRL 99 236802 (2007).

3. W.-K. Tse, B. Y.-K. Hu, and S. Das Sarma, arXiv:0801.1291v1.