Theory of epitaxial graphene

点击翻译按钮获取中文摘要

The rapid progress of epitaxial graphene technology has opened a wide vista of new methods for the controllable modification of graphene properties and the design of novel graphene-based structures. These structures include graphene epitaxial layers on various SiC facets and various SiC polytypes, quasi-freestanding graphene obtained by foreign atom intercalation into the SiC-graphene interface, and a rich variety of multilayer graphenes, in particular rotationally faulted graphene multilayers. Theoretical understanding of these systems is, at present, far from complete. Even for the most intensively studied systems, graphene on the Si- and C- terminated faces of SiC, many features await explanation, whereas the properties of graphene on the high-indexed SiC facets and on the non-polar surfaces remain theoretically unexplored. In this proposal, we aim at a detailed understanding of these systems including the role of the interface states, the role of the substrate facet choice, the properties of magnetic and non-magnetic impurities in both epilayers and multilayers, and the electronic and vibrational characteristics of the graphene-SiC interface. Notably, a very rich and novel physics of rotationally faulted graphene multilayers will be studied, in particular the electron localization at small angles, transport phenomena, and the phonon spectrum. We shall employ ab-initio DFT methods in combination with an efficient tight-binding approach tailored for graphene-based systems, as well as analytical models based on appropriately modified Dirac-Weil Hamiltonians.