Ni（111）衬底上石墨烯纳米岛锯齿形边缘的稳定和重构
Susbtrate-Induced Stabilization and Reconstruction of Zigzag Edges in Graphene Nanoislands on Ni(111)
摘要：
我们结合扫描隧道显微镜（STM）和密度泛函理论（DFT）的实验观察，揭示了Ni（111）上石墨烯最稳定的边缘结构以及堆叠驱动的激活和抑制边缘重构的作用。根据最外层碳原子相对于中空和顶部Ni位点的位置，锯齿形边缘具有非常不同的能量。三角形石墨烯纳米岛仅由更稳定的锯齿形中空边缘约束。在六边形纳米岛中，其被几何形状约束为沿着其周边交替的锯齿形中空和锯齿形顶部边缘，只有中空边缘是稳定的，而顶部边缘自发地重建成（57）五边形-七边形结构。原子分辨的STM图像与石墨烯和Ni位点的顶面-fcc或顶面-hcp外延堆叠一致，其中前者受到DFT的青睐。最后，我们发现，有一个一对一的关系之间的边缘类型，石墨烯堆叠，和取向的石墨烯岛。
英文摘要：
We combine experimental observations by scanning tunneling microscopy (STM) and density functional theory (DFT) to reveal the most stable edge structures of graphene on Ni(111) as well as the role of stacking-driven activation and suppression of edge reconstruction. Depending on the position of the outermost carbon atoms relative to hollow and on-top Ni sites, zigzag edges have very different energies. Triangular graphene nanoislands are exclusively bound by the more stable zigzag hollow edges. In hexagonal nanoislands, which are constrained by geometry to alternate zigzag hollow and zigzag top edges along their perimeter, only the hollow edge is stable whereas the top edges spontaneously reconstruct into the (57) pentagon-heptagon structure. Atomically-resolved STM images are consistent with either top-fcc or top-hcp epitaxial stacking of graphene and Ni sites, with the former being favored by DFT. Finally, we find that there is a one-to-one relationship between the edge type, graphene stacking, and orientation of the graphene islands.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
