Plasmonic excitations and transport properties of graphene ribbons and dots

石墨烯的纳米结构开启了原本无间隙的二维石墨烯功能化的可能性。在此资助期内，纳米结构石墨烯的几个基本物理方面将成为我们工作的重点：除了波导，这是等离子体动力学的一个重要问题，间隙打开和边缘通道状态将使用适当设计的纳米结构进行研究。利用四尖端STM/SEM和角度分辨高分辨电子能量损失谱（EELS），系统研究石墨烯纳米结构中的电子输运性质和集体激发与带宽度、几何形状、磁性杂质等掺杂剂吸附以及温度的关系。正如最近所证明的那样，在适当设计的SiC(0001)-MESA结构上生长的纳米带结构显示出特殊的弹道输运特征，具有极大的弹性平均自由程长度（300K时为10 μ m）。利用光学光刻技术，光带的宽度和几何形状都将被系统地修改。因此，我们希望获得对边缘状态、带隙和电子子带的可控访问。处理的路线甚至允许生长相同纳米结构的大型集成，因此空间平均技术（ARPES，拉曼，EELS）可以应用于补充STM/STS和本地传输数据。不同的吸附物在不同的石墨烯载体上的插层作为一种重要的功能化技术将被深入研究。这项技术有助于研究石墨烯纳米结构中的边缘装饰，以及化学势的变化和与衬底的修饰相互作用。

Nanostructuring of graphene opens the possibility to functionalize the originally gap-less 2D-graphene. Several fundamental physical aspects of nanostructured graphene will be in the focus of our efforts during this funding period: Besides wave guiding, which is an important issue for plasmonics, gap opening and edge channel states will be studied using appropriately designed nanostructures. Electronic transport properties and collective excitations in graphene nanostructures will be systematically studied as a function of ribbon width, geometry, adsorption of dopants including magnetic impurities, and as a function of temperature by means of 4-tip STM/SEM and angle resolved high resolution electron energy loss spectroscopy (EELS). As recently demonstrated, nanoribbon structures grown on appropriately designed SiC(0001)-MESA structures reveal an exceptional ballistic transport signature with extremely large elastic mean free path lengths (10 mu m at 300K). Using optical lithography, both the width and geometry of the ribbons will be systematically modified. Thus we want to gain controlled access to edge states, band gaps and electronic subbands. The route of processing even allows to grow large ensembles of identical nanostructures, so that spatially averaging techniques (ARPES, Raman, EELS) can be applied to complement STM/STS and local transport data. Intercalation with different adsorbates on various graphene supporting substrates will be studied intensely as a further important technique of functionalization. This technique facilitates studies of edge decoration in graphene nanostructures, in addition to shifts of the chemical potential and modified interaction with the substrate.