Interfacial Effect On Electronic Structure For Germanene

The scientific researchers pay much attention on two-dimensional materials when we realized that two-dimensional materials do exist in nature after the successful fabrication of graphene by mechanical exfoliation in 2004. These materials have great application prospect and value because of their electrons properties and unique geometry. Thus, searching and perfecting new materials is becoming increasingly urgent. And people are no longer satisfied with the production in nature with the development of science and technology. The progress of human civilization and the development of science provide us the technology to support environment. As the complexity of materials and the accuracy of first-principles, first-principles calculations can help people design the new materials and predict physical properties. At the same time, it provides us a theoretical support for the fabrication of the experimental workers.Germanene has more application prospects than graphene in the semiconductor industry as two-dimensional materials, because of the strong spin orbit coupling and well compatibility with conventional semiconductor silicon. Until now, the free-standing germanene still can't be synthesized in the experiment, but need the support of substrate. Based on above, we study the influence of germanene configuration and electrons properties from metal substrates materials, and design the preparation solution for the free-standing germanene.(1) We have investigated stable and metastable germanene structure on Al(111), Au(111), and Pt(111) substrates and study the impact of their electronic structure from these metal substrates with first-principle calculations. The results show that there could have nine stable or metastable germanene structure on the metal substrates. Comparing with the experimental information, we find that Al(111)-a, Au(111)-b and Pt(111)-c are these structures synthesized on the Al(111), Au(111) and Pt(111) substrates in the experiment. The Dirac electronics states are preserved in Au(111)-b and Pt(111)-b germanene structure and others are completely destroyed.(2) Manufacturing germanene with surface passivated by hydrogen atoms under control of chemical method. In order to fabricate free-standing germanene, we design the sandwich structure to make the dehydrogenation of germanene surface come true. The investigation showed that dehydrogenation barrier significantly reduced with the decrease of the interlayer distance dGS. When the layer spacing is 4 ?, the hydrogen atoms spontaneously separate germanene surface, so it is the ideal dehydrogenation distance. Through analysis of germanene electrics structure after dehydrogenation, we find that the Dirac electrons properties are preserved in the obtained germanene. Our results showed that the sandwich structure can successfully dehydrogenized. At the same time, the obtained germanene is naturally encapsulated by the sandwiched surfaces after dehydrogenation. In this paper, the investigation provide the theoretical reference to frabrication germanene.