Atomistic theory of impurity and substrate effects in graphene

作为一种二维狄拉克材料，石墨烯为通过界面和吸附来操纵其电子性质提供了独特的可能性。因此，我们的目标是提供一个基于第一性原理的理论，该理论可以解释和预测石墨烯中电子系统对底物和吸附的响应，并将其与实验和低能模型联系起来。我们将探索如何通过外部电荷掺杂来控制与吸附物的化学结合，以及如何在现实环境中出现导致狄拉克点激发带隙的有序吸附相。我们将研究现实无序石墨烯的输运和光谱性质，并解释石墨烯在氢化和氟化作用下的光学性质的演变。在过渡金属和稀土吸附原子中，石墨烯上的电子相互作用是决定性的，我们的目标是在存在电子关联和衬底的情况下了解石墨烯和吸附原子的化学。我们将预测哪些吸附原子/衬底组合最适合在石墨烯中实现近藤效应和磁性。在原始的石墨烯中，由于强局域项和非局域项的共存，电子-电子相互作用是特殊的，并可能导致多体不稳定性。因此，我们的目标是研究如何通过与衬底的连接和掺杂来控制石墨烯材料中的库仑相互作用和相关的多体不稳定性。最后，石墨烯与层状绝缘体的界面可以用来构建垂直石墨烯晶体管，并通过莫尔效应来操纵低能电子结构。因此，我们的目标是建立这些石墨烯杂化结构中超晶格效应、面内和垂直电子输运的第一性原理理论。

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.