The Metallic Nature of Epitaxial Silicene Monolayers on Ag(111)
The Metallic Nature of Epitaxial Silicene Monolayers on Ag(111)
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DOI：
10.1002/adfm.201400769
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发表时间：
2014-09-01
影响因子：
19
通讯作者：
Moewes, Alexander
中科院分区：
文献类型：
--
作者：
Johnson, Neil W.;Vogt, Patrick;Moewes, Alexander
硅烯是一种二维结构，由硅原子的弯曲六边形蜂窝晶格组成。独立硅烯尚未被合成，但外延硅烯单层已被直接观察到或预测存在于许多载体上。本文通过密度泛函理论和软x射线能谱在Si L-2，L-3边缘的互补技术，研究了Ag（111）上五种不同外延硅晶的原子和电子结构。与Ag（111）底物的杂化表明，这些硅烯单层成为强金属，并确定了负责这种金属性质的特定电子相互作用。结果表明，Ag（111）上的外延硅烯不具有独立硅烯和石墨烯片所特有的狄拉克锥电子结构。
Silicene is a two-dimensional structure composed of a buckled hexagonal honeycomb lattice of silicon atoms. Freestanding silicene is yet to be synthesized, but epitaxial silicene monolayers have been directly observed or predicted to exist on a number of supporting substrates. Herein the atomic and electronic structures of five distinct epitaxial silicene morphologies on Ag(111) are examined through the complementary techniques of density functional theory and soft X-ray spectroscopy at the Si L-2,L-3 edge. Hybridization with the Ag(111) substrate is shown to cause these silicene monolayers to become strongly metallic, and the specific electronic interactions that are responsible for this metallic nature are determined. The results imply that epitaxial silicene on Ag(111) does not possess the Dirac cone electronic structure that is characteristic of freestanding silicene and graphene sheets.