O.E. Glukhova – Dr.Sc.(Phys.-Math.), Professor, Head of Department of Radiotechnique and Electrodynamics,  Saratov State University named after N.G. Chernyshevsky

E-mail: GlukhovaOE@info.sgu.ru

D.S. Shmygin – Assistant, 

Department of Radiotechnique and Electrodynamics, Saratov State University named after N.G. Chernyshevsky

E-mail: shmygin.dmitriy@gmail.com

M.M. Slepchenkov – Ph.D.(Phys.-Math.), Associate Professor, 

Department of Radiotechnique and Electrodynamics, Saratov State University named after N.G. Chernyshevsky

E-mail: slepchenkovm@mail.ru

This article is devoted to the influence of potassium atoms on the density of electronic states of graphene with columns, as well as how much charge is redistributed from potassium atoms to the carbon skeleton of the composite. The paper considers three topological models of pillared graphene – monolayer (with one layer vertically aligned and chemically connected with graphene sheets of single-layer carbon nanotubes (SWCNT)), bilayer (with two layers of SWCNTs and three graphene planes), 3D-structure. The properties of pillared graphene of each topological model were investigated on the basis of the properties of the supercells of this material. Periodic boundary conditions were applied along the X and Y directions for mono- and bilayer of pillared graphene, in all three directions for the 3D-structure. The sizes of supercells along X, Y axes were: 2.46 nm and 2.13 nm for pillared graphene monolayer, 4.92 nm and 4.26 nm for pillared graphene bilayer and 3D-structure. For the Z axis, the lattice vector length was varied for the 3D-structure from 1.6 to 4.06 nm. All composites contain single-walled carbon nanotubes (9, 9), whose length varied from 0.6 nm to 1.84 nm, the diameter was 1.212 nm. In the course of the computational experiment, it was found that the charge most actively transfers from potassium atoms to the carbon skeleton for structures in which the SWNTs length is the smallest, as well as the fact that the density of electronic states on the Fermi energy increases (up to 8.816 times) for pillared graphene bilayer and 3D-structures when adding potassium atoms in the composite. For single-layer structures, no apparent increase in the density of electron states was revealed. The charge transfer normalized by the number of potassium atoms was larger for composites with shorten carbon nanotubes for the reason that the size of the cavities in composites was smaller. For composites with a longer single-walled carbon nanotube, the size of the cavities is much larger; therefore, as the number of potassium atoms increases, some of the atoms are located in the middle of the cavity, away from the carbon frame.

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