Clustering and magnetic anisotropy of Fe adatoms on graphene
نویسندگان
چکیده
Single Fe adatoms and clusters of Fe adatoms on graphene are studied through first-principles calculations using density functional theory (DFT) and spin density functional theory (sDFT). First, we consider computational cells containing various numbers of C atoms and one Fe adatom. We calculate the binding energy, adatom height, and magnetic moment of the adatom above a few high-symmetry positions in the cell. In all cases, the binding energy increases with decreasing cell size, suggesting that clustering of the Fe adatoms is energetically favored. We also calculate the energy of various clusters of two to four Fe atoms on graphene in computational cells of various sizes, using both DFT and sDFT. These calculations again show that, both in DFT and sDFT, the Fe adatoms strongly prefer to form clusters. The energy barrier for an isolated Fe adatom to diffuse from the center of one graphene hexagon is calculated to be 0.49 eV. This barrier is reduced for an Fe atom which is one of a pair of neighboring adatoms. Finally, by including spin-orbit interactions within sDFT, we calculate the magnetic anisotropy energy of a single Fe adatom on graphene. We find that the in-plane anisotropy energy is close to zero, while the out-of-plane anisotropy energy is ∼DS2 cos2 θ where S ∼ 2.0, θ is the angle between the magnetic moment and the perpendicular to the graphene plane, and D ∼ 0.25 meV.
منابع مشابه
بررسی خواص مغناطیسی تک اتمهای فلزات واسط 3d افزوده شده بر روی بورن نیتراید شش گوشی دوبعدی
In the frame work of relativistic density functional theory, using full potential local orbital band structure scheme (FPLO), the magnetic properties of single 3d transition metals (3d-TM) adsorbed on 2D hexagonal boron nitride (2D h-BN) are investigated. Binding energies between 3d-TM adatoms and 2D h-BN in three different compositions, local spin magnetic moments of 3d-TM and total spin magne...
متن کاملOrbital magnetism of transition-metal adatoms and clusters on the Ag and Au„001... surfaces
We present ab initio calculations of the orbital moments and magnetocrystalline anisotropy energies for 3d , 4d , and 5d transition-metal adatoms and for some selected small clusters on the ~001! surfaces of Ag and Au. The calculations are based on the local density approximation of density functional theory and apply a fully relativistic Koringa-Kohn-Rostoker Green’s function method. Due to th...
متن کاملMagnetic anisotropy of graphene quantum dots decorated with a ruthenium adatom
The creation of magnetic storage devices by decoration of a graphene sheet by magnetic transition-metal adatoms, utilizing the high in-plane versus out-of-plane magnetic anisotropy energy (MAE), has recently been proposed. This concept is extended in our density-functional-based modeling study by incorporating the influence of the graphene edge on the MAE. We consider triangular graphene flakes...
متن کاملTailoring the magnetism of Co atoms on graphene through substrate hybridization.
We determine the magnetic properties of individual Co atoms adsorbed on graphene (G) with x-ray absorption spectroscopy and magnetic circular dichroism. The magnetic ground state of Co adatoms strongly depends on the choice of the metal substrate on which graphene is grown. Cobalt atoms on G/Ru(0001) feature exceptionally large orbital and spin moments, as well as an out-of-plane easy axis with...
متن کاملThe electronic and diffusion properties of metal adatoms on graphene sheets: a first-principles study
We use first-principles calculations to investigate the geometric, electronic and magnetic properties of metal adatoms on two typical graphene substrates (monolayer and bilayer). Firstly, we study the adsorption behaviors and the doping effects of metal atoms on pristine and defective bilayer graphene sheets (PBG and DBG). It is found that the metal doping in DBG sheets is more stable than that...
متن کامل