Electronic and geometric corrugation of periodically rippled, self-nanostructured graphene epitaxially grown on Ru(0001)
Electronic and geometric corrugation of periodically rippled, self-nanostructured graphene epitaxially grown on Ru(0001)
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DOI：
10.1088/1367-2630/12/9/093018
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发表时间：
2010-09-13
影响因子：
3.3
通讯作者：
Miranda, Rodolfo
中科院分区：
文献类型：
--
作者：
Borca, Bogdana;Barja, Sara;Miranda, Rodolfo
在Ru(0001)衬底上外延生长的石墨烯在扫描隧道显微镜(STM)图像中显示出明显有序的山丘和山谷图案。这些观测到的“涟漪”在多大程度上是结构性的或电子性的，最近一直存在很大争议。超高分辨率STM图像和氦原子衍射数据的结合表明：(I)石墨烯晶格相对于Ru晶格旋转，(Ii)由He衍射确定的结构波纹比预测的(1.5埃)小得多，也比X射线衍射或低能电子衍射报告的结构波纹小得多。相反，当新的空间局域电子态进入STM的能量窗口时，电子波纹足够强，足以扭转+2.6V以上的山丘和山谷之间的对比。大的电子波纹导致了由电子和空穴组成的纳米结构的周期性景观。
Graphene epitaxially grown on Ru(0001) displays a remarkably ordered pattern of hills and valleys in scanning tunneling microscopy (STM) images. The extent to which the observed 'ripples' are structural or electronic in origin has been much disputed recently. A combination of ultrahigh-resolution STM images and helium atom diffraction data shows that (i) the graphene lattice is rotated with respect to the lattice of Ru and (ii) the structural corrugation as determined from He diffraction is substantially smaller (0.15 angstrom) than predicted (1.5 angstrom) or reported from x-ray diffraction or low-energy electron diffraction. The electronic corrugation, on the contrary, is strong enough to invert the contrast between hills and valleys above +2.6V as new, spatially localized electronic states enter the energy window of the STM. The large electronic corrugation results in a nanostructured periodic landscape of electron and hole pockets.