Large effect of metal substrate on magnetic anisotropy of Co on hexagonal Boron Nitride
Iker Gallardo, Andres Arnau, Fernando Delgado, Romana Baltic, Aparajita Singha, Fabio Donati, Christian Wäckerlin, Jan Dreiser, Stefano Rusponi and Harald Brune
New Journal of Physics 21, 073053 (2019)
We combine x-ray absorption spectroscopy and x-ray magnetic circular dichroism with first principles density functional theory calculations and a multi-orbital many-body Hamiltonian approach to understand the electronic and magnetic properties of Co atoms adsorbed on hexagonal boron nitride (h-BN) grown on Ru(0001) and on Ir(111) substrates. The x-ray spectral shape reveals, for both substrates, an electronic configuration close to 3d8, corresponding to a spin S=1. We observe a large out-of-plane magnetic anisotropy (14 meV) for Co on h-BN/Ru(0001), while Co on on h-BN/Ir(111) is almost isotropic. Our analysis reveals that the dissimilar magnetic anisotropy originates from different Co adsorption sites, namely atop-N on h-BN/Ru(0001) and 6-fold hollow on h-BN/Ir(111).