Dr. Felipe H. da Jornada
Advisor: Professor Steven G. Louie, Department of Physics
Since the experimental isolation of graphene in 2004, there has been tremendous interest in studying quasi-2D systems. These materials are atomically thin, and display many fascinating properties not found in regular bulk materials. Their high carrier mobility, high optical absorption, and tunable electronic properties make these quasi-2D materials ideal building blocks for next-generation chips and solar-cell devices. My dissertation seeks to explain, from a fundamental physics perspective, why these quasi-2D materials behave like this. In order to give unbiased predictions of how these systems behave, we use theoretical frameworks that do not rely on experimental fitting parameters, and use supercomputers to perform calculations. We show that many of these interesting electronic and optical properties stem from the weak electronic screening in these materials, which a result of their reduced dimensionality and which often cannot be accounted for with simpler models. We also introduce new computational approaches to make these calculations much faster and more realistic, and we show, for instance, that even the substrate that holds these materials in experiments can dramatically influence the measured properties.