After more than 15 years of intense research, graphene, a prototypical bidimensional material, has not exhausted its interest. One example is given by the combination of graphene with metal surfaces that can open new perspectives in the engineering of spintronic devices, high-density magnetic storage, and permanent magnets. Graphene grown on metal surfaces undergoes various structural transformations that depend on the specific metal. These alterations can be used in the design of new spintronic devices.
Aware of the fundamental and technological relevance of the field, a team of scientists at CNR Nano, Modena, investigated the influence of the presence of oxygen in Graphene grown on Cobalt/Iridium (Co/Ir) interfaces and recently published the results in Physical Review Materials. The theoretical calculations (using the MaX flagship code QuantumESPRESSO) were performed by the team composed of D. L. Valido, A. Ferretti, D. Varsano, E. Molinari and C. Cardoso, using computational resources from the Marconi100 machine at CINECA, provided by the Italian ISCRA program.
The graphene-Co/Ir interfaces were simulated considering its realistic structure in which graphene assumes a peculiar egg-box shape. It included more than 600 atoms with all their subtle and complex interactions, described using first-principles quantum mechanics through density functional theory. The use of the new accelerated hybrid architectures (CPUs+GPUs) available at Cineca, was fundamental for the simulation of such a large system. The results of these simulations highlighted the role of oxygen atoms in determining the structure and electronic properties of graphene, supporting the idea that oxygen intercalation could be used as a switch for the electronic behavior of graphene/metal interfaces.
