Ni Clusters Embedded in Multivacancy Graphene Substrates

ORAZI, VALERIA; AMBRUSI, R.E.; MORELLI, G. A.; MARCHETTI, J.M.; JUAN, A.; PRONSATO, M.E.

Congreso; 2020 Express Conference on the Physics of Materials and Their Applications in Energy Harvesting; 2020

Graphene is a material composed only of carbon atoms with a honeycomb structure, where electrons that interact with the lattice periodic potential behave as massless Dirac fermions. This particular feature leads to a linear dispersion relationship between the π and π* bands at the Fermi energy near the point K, which is described by touching Dirac cones at the Fermi level, having as a zero-gap semiconductor behavior without magnetic moment. Doping graphene can lead to the aperture of a band gap and interesting changes in its electronic structure that can induce different applications for graphene materials.TM atoms bind with C atoms via strong covalent bonds, so they can act as effective substitutional dopants. However, because the TM?TM interaction is much stronger than the TM-host materials, TM atoms tend to form clusters on the sheet surface, for that reason to achieve a high dispersion of the metal the introduction of defects like vacancies are necessary. This property is fundamental for the adsorption process like the enhancement in for CO2 adsorption capacity by depositing Ni clusters onto defective graphene surfaces [3] or hydrogen storage. In the present study, we analyzed the interactions of small Ni4 cluster embedded in graphene multivacancy systems and its structural stability based on systems with various numbers of vacancies and configurations. The band structures as well as magnetic and electronic properties were included.