Plasmonic excitations and transport properties of graphene ribbons and dots

石墨烯的纳米结构化打开了使最初无间隙的2D-石墨烯功能化的可能性。纳米结构石墨烯的几个基本物理方面将是我们在此资助期间努力的重点：除了波导，这是等离子体的一个重要问题，间隙开放和边缘通道状态将使用适当设计的纳米结构进行研究。石墨烯纳米结构中的电子输运性质和集体激发将通过4-tip STM/SEM和角分辨高分辨率电子能量损失谱（EELS）系统地研究作为带宽度、几何形状、包括磁性杂质的掺杂剂的吸附的函数以及作为温度的函数。正如最近所证明的那样，在适当设计的SiC（0001）-梅萨结构上生长的纳米结构显示出具有极大弹性平均自由程长度（300 K时为10 μ m）的特殊弹道输运特征。使用光学光刻，带的宽度和几何形状将被系统地修改。因此，我们希望获得对边缘态、带隙和电子子带的受控访问。处理的路线甚至允许生长相同的纳米结构的大集合，使得空间平均技术（ARPES，拉曼，EELS）可以应用于补充STM/STS和本地传输数据。插层与不同的吸附在各种石墨烯支撑基板将深入研究作为进一步的功能化的重要技术。这种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基底的改性相互作用。

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.