Electronic and optical properties of group IV two‐dimensional materials

The microscopic study of complex systems has reached a high level of accuracy that allows for a deep understanding of their structure, electronic properties, and optical spectra. The theoretical investigation of surfaces is nowadays routinely done within density functional theory, for ground state properties, and, with a larger computational load, within many‐body perturbation theory, for excited states properties. In this paper we present and discuss examples of calculations for group IV two‐dimensional systems such as a clean silicon surface, a tin–germanium interface, graphene, and graphane, pointing out the importance of a pertinent treatment of many‐body effects.