Tuning the spin texture of graphene with size-specific Cu _n clusters: a first-principles study

Abstract

The size dependent interaction of Cun (n = 1‒5) clusters with pristine and defective (C-vacancy) graphene is studied by employing density functional theory. The computed binding energies are in the range of ~0.5 eV for pristine graphene and ~3.5 eV for defective graphene, indicating a much stronger interaction in the later system. The induced spin-orbit coupling interaction, due to the proximity of the Cun cluster, is studied with non-collinear spin-polarized simulations. The clusters cause a spin splitting in the order of few meV. The resultant low energy bands spin textures are also computed, and a spin-valley coupling in the case of even atom clusters on pristine graphene is predicted, leading to the emergence of a spin lifetime anisotropy. For defective graphene, a complete out-of-plane spin texture and a large spin splitting of 40-100 meV is obtained for Cun (n = 1, 2, 3, 5) clusters due to local magnetic moment. On the other hand, for Cu4/defective graphene, having no net magnetic moment, the spin-valley coupling prevails close to the band edges.

Stability and Electronic Structure of Nitrogen-Doped Graphene-Supported Cun (n = 1–5) Clusters in Vacuum and under Electrochemical Conditions: Toward Sensor and Catalyst Design

“… 52 Furthermore, on pristine and on single vacancy defected graphene, the Cu 3 and Cu 5 were found to be the most stable, respectively. 52 …”

“…It is worth noting that the interaction energies between the substrates and the metal clusters are roughly twice as high with nitrogen-doped graphene compared to pristine graphene or graphene with a vacancy . Furthermore, on pristine and on single vacancy defected graphene, the Cu 3 and Cu 5 were found to be the most stable, respectively …”

“…The Bader charge analysis showed that among the clusters, N 4 V 2 –Cu 4 exhibits the largest charge transfer, Δ Q = 1.39e – and also the highest number of copper–nitrogen bonds, in line with its extended stability. It is worth noting that the interaction energies between the substrates and the metal clusters are roughly twice as high with nitrogen-doped graphene compared to pristine graphene or graphene with a vacancy . Furthermore, on pristine and on single vacancy defected graphene, the Cu 3 and Cu 5 were found to be the most stable, respectively …”

“…It is worth comparing the Cu n cluster binding modes on N 4 V 2 to those on graphene. Murugesan et al 52 showed that Cu n ( n = 1–4) clusters prefer to bind to pristine graphene with a single copper atom with planar geometry, where the plane of the cluster is perpendicular to the one of the substrate. On the other hand, the plane of cluster Cu 5 is parallel to the one of graphene.…”

“…We also study the electronic structures using advanced symmetry considerations. Murugesan et al 52 studied Cu n ( n = 1–5) clusters deposited on free and single vacancy-defected graphene surface using DFT computations. They focused on possible applications in the field of spintronics.…”