First principles investigations of layered materials and their interaction with support

Abstract

Layered materials form an interesting class of materials wherein, atoms within the plane of the material interacts amongst themselves with strong covalent bonds, while along the direction normal to the plane, the interaction is primarily through weak van der Waals forces. Graphene was the first layered material discovered, which led to an enormous research activity of exploring different other layered materials. In addition to studying pristine layered materials, there are efforts to tune their properties by chemical modifications for various applications like electronic devices, environmental benefits, hydrogen storage, etc. Moreover, when placed on substrates, the properties of the supported layered materials can be significantly modified either through physical or chemical interactions with the substrate. In this talk I will discuss the effects of chemical modifications and interactions with support on the properties of layered materials which are determined using density functional theory calculations. In our study we have restricted to lattice matched supports. In particular, we have studied the changes in the electronic properties of a graphene sheet on hydrogenation, creation of C vacancies and decorating the vacancies with B, N and Co. Further, I will talk about the effects on the properties of modified graphene when it is placed on transition metal substrates of lattice-matched (111) surfaces of Ni, Co and Cu. Additionally I will discuss tunning of interface properties at the interface of semihydrogenated graphene and Ni(111) upon oxygen intercalation. Apart graphene (monoatomic layered material), I will also talk about our investigations on another novel class of layered material, namely GaSe, where there are four atomic layers, two layers of Ga atoms sandwiched between two layers of Se atom. In these material, in collaboration with experimental groups, we have investigated the properties of these pristine materials and the effect of Mn doping in them.