Atomistic theory of impurity and substrate effects in graphene

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Being a two-dimensional Dirac material, graphene offers unique possibilities for manipulating its electronic properties by interfacing and adsorbates. It is thus our goal to provide a first-principles based theory which can explain and predict the response of the electron systemin graphene to substrates and adsorbates and which will be linked to experiments and low-energy models. We will explore how chemical binding to adsorbates can be controlled by external charge doping and how ordered adsorbate phases leading to excitation gaps at the Dirac point can emergefor graphene in realistic environments. We will study transport and spectral properties of realistically disordered graphene and explain the evolution of optical properties of graphene under hydrogenation and fluorination. In transition metal and rare earth adatoms on graphene electronic interactions are decisive and we aim to understand the chemistry of graphene and adatoms in presence of electron correlations and substrates. We will predict which adatom / substrate combinations are best suited to realize a Kondo effect as well as magnetism in graphene. Already in pristine graphene mono-, bi- or trilayers electron-electron interactions are special due to the coexistence of strong local and non-local terms and can lead to many-body instabilities. It is therefore our goal to study how Coulomb interactions and related many-body instabilities in graphene-based materials can be controlled by interfacing with substrates and doping. Finally, interfacing of graphene with layered insulators can be used to build vertical graphene transistors and to manipulate the low energy electronic structure by moiré effects. We thus aim to build a first-principles theory of superlattice effects, in-plane and vertical electron transport in these graphene hybrid structures.