Department of Physics and Laboratory for Surface Studies, University of Wisconsin, Milwaukee, Wisconsin 53211, USA.
Phys Rev Lett. 2010 Aug 20;105(8):085502. doi: 10.1103/PhysRevLett.105.085502. Epub 2010 Aug 19.
Using scanning tunneling microscopy with Fe-coated W tips and first-principles calculations, we show that the interface of epitaxial graphene/SiC(0001) is a warped graphene layer with hexagon-pentagon-heptagon (H(5,6,7)) defects that break the honeycomb symmetry, thereby inducing a gap and states below E(F near the K point. Although the next graphene layer assumes the perfect honeycomb lattice, its interaction with the warped layer modifies )the dispersion about the Dirac point. These results explain recent angle-resolved photoemission and carbon core-level shift data and solve the long-standing problem of the interfacial structure of epitaxial graphene on SiC(0001).
使用带有 Fe 涂层的 W 尖端的扫描隧道显微镜和第一性原理计算，我们表明外延石墨烯/SiC(0001)界面是一个具有六边形-五边形-七边形（H(5,6,7))缺陷的扭曲石墨烯层，破坏了蜂窝对称性，从而诱导了一个能隙和在 K 点附近的 E(F 以下的态。尽管下一个石墨烯层采用了完美的蜂窝晶格，但它与扭曲层的相互作用改变了 ) 狄拉克点附近的色散。这些结果解释了最近的角分辨光发射和碳芯能级位移数据，并解决了外延石墨烯在 SiC(0001)上的界面结构的长期问题。
