2D-crystals with five interatomic bonds of Kepler nets type

Background. Well-known 2D-crystalline materials are graphene and graphene-like structures in the form of flat atomic grids with hexagonal cells. Meanwhile, it is only one of eleven possible flat grids consisting of regular polygons (Kepler nets). Five more of them describe the so-called supracrystals, proposed by the researchers earlier and investigated by some other authors as well. The purpose of this paper is to research a possibility of steady existence of 2D-crystalline lattices in the form of Kepler nets of types $343^2 4$, $3^3 4^2$ and $3^4 6$ (designations are given in Schläli's symbols). Materials and methods. The research objects are 2D-crystalline structures consisting of atoms of the fifth group (P, As, Sb, Bi) and the sixth group (S, Se, Te) of the periodic table. Numerical calculations of interatomic bonds length corresponding to the equilibrium state of structure were made on the basis of DFT methods using the VASP software package ver. 4.6. Results. It is shown that among such new 2D-crystals can be metals, as well as dielectrics and semiconductors. Besides, some of them can possess pyroelectric and piezoelectric properties. Conclusions. New Keplerian crystals can be used for nanoelectronic and nanoelectromechanical devices creation.