Ab initio study of graphene on SiC
Ab initio study of graphene on SiC
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DOI：
10.1103/physrevlett.99.076802
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发表时间：
2007-08-17
影响因子：
8.6
通讯作者：
Pankratov, Oleg
中科院分区：
文献类型：
--
作者：
Mattausch, Alexander;Pankratov, Oleg
用密度泛函方法研究了硅端和碳端1x1-6H-碳化硅表面的单层和双层石墨烯。我们表明，与先前的假设相反，第一碳层是共价键合在衬底上的，不能对实验观察到的石墨烯类型的电子光谱负责。自立式石墨烯的特征光谱出现在第二碳层上，第二碳层显示出与底层结构的弱范德华成键。对于硅端衬底，界面是金属的，而在C面上，对于单或双石墨烯覆盖，界面分别是半导体或半金属。
Employing density-functional calculations we study single and double graphene layers on Si- and C-terminated 1x1-6H-SiC surfaces. We show that, in contrast with earlier assumptions, the first carbon layer is covalently bonded to the substrate and cannot be responsible for the graphene-type electronic spectrum observed experimentally. The characteristic spectrum of freestanding graphene appears with the second carbon layer, which exhibits a weak van der Waals bonding to the underlying structure. For Si-terminated substrate, the interface is metallic, whereas on C face it is semiconducting or semimetallic for single or double graphene coverage, respectively.