Estudo teórico de monocamada e bicamada de grafeno em superfície de óxido de háfnio amorfo

• Ano de defesa: 2015
• Autor(a) principal: Vitória Júnior, Moacir Cézar da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Física; Centro de Ciências Exatas; UFES; Programa de Pós-Graduação em Física
• Palavras-chave em Português: Graphene; Bilayer graphene; a-HfO2; Magnetic moment; DFT; Grafeno; Funcionais de densidade; Momento magnético; Física; 53
• Link de acesso: http://repositorio.ufes.br/handle/10/7461

In this work, we have used the first principle calculations based on Density Funcional Theory (DFT) to investigate the interfaces between graphene monolayer (G) and graphene bilayer (BLG) on amorphous hafnium oxide (a-HfO2) surface. We have also considered carbon and oxygen vacancies in graphene sheets and amorphous hafnium oxide, respectively. In particular, we have studied different interfaces: (i) G(VC)/a-HfO2, (ii) G(VC)/a-HfO2(VO) and (iii) BLG(VC)/a-HfO2. From point of view energetic stability, our finds showed that the interfaces formation are an exothermic process, in the case (i) and (iii) ruled by van der Waals interactions. However, for interface (ii) the formation energy is two times higher than the others and presence of the chemical bonds was also observed. Moreover, from point of view structural, the presence of the substrate induce a corrugation on graphene sheets and the interfacial equilibrium distance between them is about 3,0 Å. Additionaly, our results showed that there is a total magnetic moment for interfaces (i) and (iii). Thus, our finds reveal that the structural, electronic and magnetic properties of the graphene sheets are very sensitive to presence of the substrate