Spintronics based on chemically functionalized graphene

The objective of this project is to use individual sheets of chemically modified graphene as electronic components of spintronic devices. As a first type of chemical functionalization, hydrogen atoms or organic molecules shall be covalently linked to the graphene under partial saturation of its π-conjugated lattice, such that unpaired electrons (spins) are created. Along these lines, it is planned to use nanostructured catalysts in order to achieve certain arrangement patterns of the functional groups. A second strategy involves the non-covalent adsorption of molecular magnets on the graphene layers. Magnetic measurements on such hybrid materials shall provide information on the spin dynamics of the molecular magnets and thus on the extent of their interaction with graphene. Furthermore, graphene-based spin valves shall be realized from both types of functionalized graphene. The electrical conductivity of these devices is envisioned to be controlled by the relative spin orientation between the injected carriers and the coupled molecular magnet. Finally, with the aim of gaining a better understanding of the spin dynamics in these devices, complementary tunnel experiments are planned to probe spin excitations in the covalently-functionalized graphene and the molecule/graphene hybrids.

Fig.1: Schematic depiction of the interactions of a spin system (represented by a blue arrow) with underlying graphene, involving dipolar interactions (dark orange), hyperfine interactions (light orange), phonons (green) and the electron gas (red). The sum of each of these contributions is expected to govern the performance of corresponding spintronic devices.