應用第一原理密度泛函理論研究鍍在過渡金屬上的單層石墨烯的能帶結構

Ab initio Calculations of Epitaxial Graphene Layer on Transition Metal Substrates

葉紘宇(Hung-Yu Yeh)

指導教授 ： 郭光宇

國立臺灣大學/理學院/物理研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.01903

摘要

單層石墨烯特有的電子性質，並預測可將其特有的性質應用在電子元件上，是近幾年來受到廣大的注意與研究的新穎材料。而目前製造出單層石墨烯有兩種方法：其一是利用微機械力分裂法從石墨上撕出單層石墨烯，其二為在金屬基底上鍍上單層石墨烯。在此研究中我們利用了密度泛函理論去計算被鍍在釕、鎳、銥上的單層石墨烯的能帶與電子形質，可以看出單層石墨烯與基底間的交互作用。另一方面，我們也計算在考慮了自旋軌道偶合作用後，單層石墨烯能帶分裂的情形。
我們發現鍍在基底上的第一層單層石墨烯跟基底的金屬原子有極大的交互作用，所以第一層單層石墨烯在倒晶格空間中的狄拉克點並不再有單層石墨烯的線性能帶。而想要在基底上製造出類似單層石墨烯的線性能帶的方法有二，其一是在第一層單層石墨烯和鎳基底間插入一層金原子層，其二為在釕上鍍上第二層石墨烯。考慮了自旋軌道偶合作用後，我們發現在考慮了自旋軌道偶合作用後，基底上似單層石墨烯線性能帶的分裂大小大約等於單層石墨烯現性能帶分裂的大小。

關鍵字

第一原理 ； 單層石墨烯 ； 釕 ； 鎳 ； 銥 ； 基底 ； 能帶

並列摘要

Graphene has recently been investigated because of its fascinating electronic properties, and show great promise for electronic device. The primary methods for producing graphene are micromechanical cleavage of graphite and epitaxial growth. In this study, epitaxial graphene on metal substrate Ru(0001), Ni(111) and Ir(111) were studied by density functional theory (DFT) calculations. The interaction between graphene and substrate was investigated. The spliting of epitaxial graphene band result from spin-orbit coupling was also investigated.
We find that the first epitaxial graphene layer on the pure Ru(0001), Ni(111) and Ir(111) are significantly influenced by substrates. Thus, its electronic properties differ significantly from that of the isolated graphene sheet. The quasifreestanding graphene which displays a linear Dirac cone with the Dirac point shifted slightly from the Fermi level could be produced in two ways. One is intercalating one layer Au between graphene and Ni(111) substrate; the other is plating second graphene layer on Ru(0001). After considering spin-orbit coupling, the spliting of quasifreestanding graphene linear band is about same with the spliting of isolated graphene.

並列關鍵字

graphene ； epitaxial ； ab initio ； Ru ； Ni ； Ir ； band structure

參考文獻

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