Optical Spectroscopy and Phonon Self-Energy Renormalizations in Carbon Materials

For over two decades, carbon-based materials have been the focus of intense research, accumulating two Nobel prizes (fullerenes-1996 and graphene-2010) and an uncountable number of solutions that aim, almost always, technological applications in the nanometer scale such as solar cells, transistors and gas sensors. In this colloquium, I will discuss my recent contributions to the development of basic research in carbon materials. More specifically, I will explain how optical spectroscopy can be merged with electronic devices to probe basic properties of carbon materials which are tightly related to electron, phonons as well as their mutual interactions. More specifically, a discussion about phonon self-energy renormalizations in single and double layer graphene involving phonons with zero momentum (q = 0) and non-zero momentum (q ≠ 0) will be addressed by showing that they have opposite behaviors with changing the graphene’s Fermi level energy EF. These different behaviors exhibited by q = 0 and q ≠ 0 phonons serve as a new and efficient tool to assign phonons, combination of phonons and phonon overtones. Finally, I will briefly address some topics related to my work on the development of new carbon materials and give my perspectives on the next steps of my research.