Finding the right substrate support for magnetic superatom assembly from density functional calculations.

In order to find the right support to form assemblies of superatoms with useful magnetic properties, adsorption of the magnetic superatom FeCa8 on different types of substrates is studied using first-principles electronic structure methods. FeCa8 interacts strongly with oxide and metal substrates and its structure and magnetic properties are destroyed. Interaction between FeCa8, and graphene and hexagonal BN (h-BN) are weak, and its structure is retained on these substrates. Dimers of FeCag are also found to be stable on both h-BN and graphene. While the magnetic interaction between two FeCa8 units deposited on h-BN involves only direct exchange, substrate mediated RKKY interaction also plays a role on graphene. Consequences of these for the magnetic properties of the assemblies are discussed. [ABSTRACT FROM AUTHOR]