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arXiv · 1611.08246

Vacancy in graphene: insight on magnetic properties from theoretical modeling

Ana M. Valencia·Marilia J. Caldas
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Abstract

Magnetic properties of a single vacancy in graphene is a relevant and still much discussed problem. The experimental results point to a clearly detectable magnetic defect state at the Fermi energy, while calculations based on density functional theory (DFT) yield widely varying results for the magnetic moment, in the range of $μ=1.04-2.0$ $μ_{B}$. We present a multi-tool \textit{ab initio} theoretical study of the same defect, using two simulation protocols for a defect in a crystal (cluster and periodic boundary conditions) and different DFT functionals - bare and hybrid DFT, mixing a fraction of Hartree-Fock exchange (XC). Our main conclusions are two-fold: First, we find that due to the $π$-character of the Fermi-energy states of graphene, inclusion of XC is crucial and for a single isolated vacancy we can predict an integer magnetic moment $μ=2μ_{B}$. Second, we find that due to the specific symmetry of the graphene lattice, periodic arrays of single vacancies may provide interesting diffuse spin-spin interactions.

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Ana M. Valencia, Marilia J. Caldas. 2017-05-13. Vacancy in graphene: insight on magnetic properties from theoretical modeling. https://doi.org/10.1103/physrevb.96.125431

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