Graphene-mediated exchange coupling between magnetic molecules and substrates: a DFT view

Abstract: An important research lines in magnetism is to embed the spin degrees of freedom into a molecular units. The field of molecular spintronics aims to realize molecule-based logic and storage devices, interfacing magnetic molecules with opportune substrates/electrodes. The characterization of molecule-substrate interactions is therefore very timely and has raised in the last years a broad interest in the surface physics and chemists communities. Along this line, I will present a theoretical investigation of magnetic molecule-substrate systems, and I will focus on single ion molecules, namely TM-phthalocyanines (TM=transition metals) [1,2], metallocenes (e.g. CoCp2) [3] and Ln double-deckers (e.g. TbPc2) [4,5], deposited on Ni substrates. In particular I will discuss the case where a graphene layer is interposed between the molecules and the substrate, highlighting its role in mediating the magnetic interaction. The calculations have been carried out by state-of-the-art density-functional theory methods, as implemented in the VASP and Quantum Espresso packages, comparing when possible with X-ray Magnetic Circular Dichroism experiments.
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[4] A. Candini, D. Klar, S. Marocchi, V. Corradini, R. Biagi, V. de Renzi, U. del Pennino, F. Troiani, V. Bellini, S. Klyatskaya,M. Ruben, K. Kummer, N. B. Brookes, H. Huang, A. Soncini, H. Wende, and M. Affronte, Scientific Report 6, 21740 (2016).
[5] S. Marocchi, A. Candini, D. Klar, W. Van den Heuvel, H. Huang, F. Troiani, V. Corradini, R. Biagi, V. De Renzi, S. Klyatskaya, K. Hummer, N. B. Brookes, M. Ruben, H. Wende, U. del Pennino, A. Soncini, M. Affronte, and V. Bellini, ACS Nano 10, 9353 (2016).