The understanding and tuning of the electronic properties of graphene on metals, possibly encompassing magnetism, is crucial towards the inclusion of graphene into devices, and graphene-based electronics on a large industrial scale.
The electronic properties of epitaxial Gr significantly depend on the supporting substrate: Gr grown on Ir(111) presents a rippled moiré superstructure, weakly interacting with the metallic substrate, and preserving the peculiar spectroscopic features of the Gr band-structure. Conversely, the growth of Gr onto transition metal surfaces such as Ni(111) or Co(0001) generally results in a better lattice matching at the expense of a significantly perturbed band structure.
Moreover, the use of magnetic substrates such as Co adds magnetism to the properties of interest.Gr/Co(0001) interfaces have been extensively studied and the Gr bands well characterized, however Density Functional Theory simulations show a limited agreement with ARPES measurements.
We expect to significantly improve the accuracy of the theoretical simulations by improving the level of theory adding non-locality and long-range interactions by means of GW calculations. They are however challenging due to the complexity of the theoretical methods, requiring HPC resources.
In this project we aim at the accurate characterization of the Gr/Co band structure at GW level, making use of recent methodological developments by the team members that limit the computational effort. We will use the Yambo code, a flagship code of the EU MaX “Materials Science at the Exascale” Centre of Excellence, successfully ported to GPUs and extensively benchmarked in a range of architectures, including Tier-0 machines.