Substitutional 4d and 5d impurities in graphene

arXiv:1606.00165v1We describe the structural and electronic properties of graphene doped with substitutional impurities of 4d and 5d transition metals. The adsorption energies and distances for 4d and 5d metals in graphene show similar trends for the later groups in the periodic table, which are also well-known characteristics of 3d elements. However, along earlier groups the 4d impurities in graphene show very similar adsorption energies, distances and magnetic moments to the 5d ones, which can be related to the influence of the 4d and 5d lanthanide contraction. Surprisingly, within the manganese group, the total magnetic moment of 3 μB for manganese is reduced to 1 μB for technetium and rhenium. We find that compared with 3d elements, the larger size of the 4d and 5d elements causes a high degree of hybridization with the neighbouring carbon atoms, reducing spin splitting in the d levels. It seems that the magnetic adjustment of graphene could be significantly different if 4d or 5d impurities are used instead of 3d impurities.This work has been partially supported by Project FIS2013-48286-C2-1-P of the Spanish Ministry of Economy and Competitiveness MINECO, by the Basque Government under the ETORTEK Program 2014 (nanoGUNE2014), and the University of the Basque Country (Grant No. IT-366-07). TAL acknowledge a grant provided by the MPC Materials Physics Center – San Sebastián. FA-G would like to thank the DIPC for their generous hospitality. We also acknowledge the assistance provided by the DIPC computer center (TAL, AA and FA-G).Peer reviewe