Magnetic 3d adatoms on free-standing and Ni(111)-supported graphene

Abstract

We present an extensive density functional theory analysis of the structural, electronic, and magnetic properties of isolated 3d transition metal adatoms (from Ti to Co) adsorbed on free-standing and Ni(111)-supported graphene. We discuss how the energetics of different adsorption sites is influenced by the filling of d-orbital filling across the 3d series and identify a direct correlation between the adatom-graphene distance and the degree of charge transfer. The presence of the Ni substrate is found to have stronger impact on the adatoms at the end of the series, leading to modifications of the preferred adsorption site, charge transfer, and spin properties. The magnetic exchange coupling between the spin of the adatom and the Ni magnetization changes as a function of the adatom both in sign (preferred antiferromagnetic exchange for Ti, V, and Cr, and ferromagnetic alignment for the other elements) and in magnitude (from 90 meV for Mn to ≈10 meV for Fe an Co).

1d Selective Confinement and Diffusion of Metal Atoms on Graphene

“…We thus calculate the adsorption energy of individual Co atom at high symmetry sites on valleys and ridges. Co adsorbs on the center of hexagon (H-site) on the free-standing G sheet [47][48][49] but the presence of the metallic substrate underneath G can alter the favorable adsorption site [50]. On G/Ni(100) we found that hollow sites stay the favorable ones.…”

Hybridization of an s-wave impurity with graphene lattice

“…Since its first synthesis twenty years ago [1,2], graphene has always been the most investigated material thanks to its exotic electronic and mechanical properties, in particular the Dirac fermion characteristic around the Fermi level [3,4]. These unique properties also make graphene an optimal host lattice for a wide variety of adatoms [5,6], which may lead to potential applications such as electronic devices [7], single-ion magnets [8], single-atom catalysts [9], or tuning the electronic properties by doping [10], etc. To step closer to the realization of those applications, it is crucial to understand the behaviors of impurities on graphene.…”

Магнитные Состояния В Модели Поверхностного Димера

“…Итак, в настоящей работе в дополнение к межатомному кулоновскому отталкиванию, способствующему межатомному переходу заряда [4], мы учли внутриатомное отталкивание, ведущее к спиновой поляризации поверхностного димера. Полученные для металлов результаты можно обобщить не только на случай массивных полупроводниковых (диэлектрических) подложек [2], но и на случай двумерных графеноподобных структур [3,4], в связи с чем отметим растущий интерес к исследованию адсорбции магнитных атомов на графене [20][21][22].…”