The ab initio calculations of the magnetic anisotropy of thin (to six monolayers) nickel films and iron films with unusual fcc structures formed upon intercalation of graphene with Fe atoms are presented. The data have been obtained for both the pure-surface films and the films coated with graphene. The density functional theory and the pseudopotential method are used to calculate the magnetic moments of atoms of all the layers and to determine the total energies of the structures with different orientations of magnetic moments of iron and nickel atoms with respect to the film surface. A strong influence of graphene on the magnetic properties contacting iron films is demonstrated.

Методом функционала плотности проведены ab initio расчеты электронного строения низкоразмерных систем графен-железо-никель и графен-кремний-железо. Для системы графен/Fe/Ni(111) определены зонные структуры для разных проекций спина и полные плотности состояний валентных электронов. Энергетическое положение конуса Дирака, обусловленного pz состояниями графена, слабо зависит от количества слоeв железа, интеркалированного в межслоевой зазор между никелем и графеном. Для системы графен/Si/Fe(111) определены наиболее выгодные положения атомов кремния на железе. Внедрение кремния под графен приводит к резкому уменьшению взаимодействия атомов углерода с подложкой и в значительной степени восстанавливает электронные свойства свободного графена. Pабота выполнена при частичной финансовой поддержке РФФИ (проект N 16-02-00387) и Минобрнауки РФ (задание 3.3161.2017 проектной части госзадания). Pасчеты проведены с использованием вычислительных ресурсов суперкомпьютерного центра СПбПУ. DOI: 10.21883/FTT.2017.10.44977.130

Ab initio calculations of the electron spectrum of the graphene–cobalt–nickel system were performed in the slope of the spin density functional theory (SDFT). Dispersion curves E _σ n (k) are presented; they were used to determine partial and total densities of valence electron states, and also magnetic moments of all atoms in the supercell. Energy position of the “Dirac cone” defined by p _ z states in graphene is shown to depend only slightly on the number of Co layers intercalated into the gap between the cobalt and graphene layers.

The results of ab initio calculations of the spin-polarized band structure of graphene on silicon carbide intercalated with cobalt and silicon atoms are presented. It is shown that metal and silicon atoms during intercalation are localized between the substrate and the buffer layer of carbon atoms. Initially, the cobalt layer is strongly coupled with the buffer layer. The subsequent intercalation of silicon and the formation of cobalt silicide leads to a transition from hybridized state to the formation of quasi-freestanding bilayer graphene on the surface of the system due to the transformation of the buffer layer to the second graphene layer.