The backside of graphene: functionalization by intercalation

石墨烯的背面：通过插层进行功能化

• 批准号: 242781776
• 负责人: Professor Dr. Thomas Werner Michely
• 金额: --
• 依托单位: Department Physik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/242781776?language=en
• 关键词: backside; graphene; functionalization; intercalation

As atomic layer material, the atoms of graphene are at the same time front- and backside surface atoms. Therefore, the properties of graphene depend crucially on its environment. Only if bounded on both sides by vacuum, its properties come close to the theoretical predictions for the pure, suspended material. However, the ease by which graphene is affected through contact with other materials is one of its unique features and defines an integral part of its potential for applications. In this proposal we will use intercalation, the insertion of atomic layers in between the backside of graphene and its substrate, as a tool to change its properties and its interaction with the environment on its frontside. The investigations will rely on an all in situ surface science approach to grow, modify and analyze structurally perfect graphene. Through well-defined experiments unambiguous theoretical modeling will be possible.Intercalation provides a flexible means to drastically modify the chemical potential of the Dirac electrons, providing changes an order of magnitude larger as available by external gating. As a specific tool for our research, we will use intercalation patterns providing a strong local variation of the doping level. We will explore how extreme p- and n-doping changes the nature of the chemical interaction of ionic adsorbates, organic molecules and radicals with graphene. New, hitherto unobserved phenomena in graphene are expected, such as a doping dependent molecular switching, doping dependent ordering of adatoms, or writing of chemical patterns predefined by intercalation patterns. Graphene has been proven to be an excellent spin conductor. The application potential for spintronics would greatly increase, if it would be possible to induce spin polarization in graphene. This perspective has already triggered a large effort to induce a spin-split Dirac cone through contact with ferromagnetic 3d materials. However, the strong hybridization of the d-electrons with the pi-electronic system of graphene appears to limit the applicability of this concept. To achieve a spin-split and intact Dirac cone, we explore here the use of up now uninvestigated rare earth metal intercalation layers, also in combination with ferromagnetic layers.

作为原子层材料，石墨烯的原子同时是前后表面原子。因此，石墨烯的性质在很大程度上取决于它的环境。只有在两边都有真空的情况下，它的性质才接近于纯悬浮物质的理论预测。然而，石墨烯通过与其他材料接触而受到影响的便利性是其独特的特征之一，也是其应用潜力的一个组成部分。在这个提议中，我们将使用嵌入，在石墨烯的背面和衬底之间插入原子层，作为改变其性质及其与正面环境相互作用的工具。这些研究将依靠全原位表面科学方法来生长、修饰和分析结构完美的石墨烯。通过定义良好的实验，明确的理论建模将成为可能。插层提供了一种灵活的方法来大幅度地改变狄拉克电子的化学势，提供了比外部门控大一个数量级的变化。作为我们研究的特定工具，我们将使用嵌入模式，提供掺杂水平的强局部变化。我们将探索极端p-和n-掺杂如何改变离子吸附剂、有机分子和自由基与石墨烯的化学相互作用的性质。预计在石墨烯中会出现新的、迄今为止未观察到的现象，例如依赖于掺杂的分子开关、依赖于掺杂的配原子有序，或者通过嵌入模式预先定义的化学模式的写入。石墨烯已被证明是一种优秀的自旋导体。如果能够在石墨烯中诱导自旋极化，自旋电子学的应用潜力将大大增加。这一观点已经引发了通过与铁磁三维材料接触来诱导自旋分裂狄拉克锥的巨大努力。然而，石墨烯的d电子与pi电子系统的强杂化似乎限制了这一概念的适用性。为了实现自旋分裂和完整的狄拉克锥，我们在这里探索了目前尚未研究的稀土金属插入层的使用，也与铁磁层结合使用。