Quantum chemical study of structure and properties of CrN mono- and bilayer

Lately, such materials as graphene h-BN and transition metal dichalcogenides have been widely used in various fields and have received a lot of attention owing to its numerous device applications (spintronics, photovoltaic, valleitronics). This is due to the low dimensionality and different properties from those bulk materials. At the same time, at this stage of scientific development, other two-dimensional materials have been actively studied, including carbides and nitrides of transition metals. Some of them have been experimentally obtained, characterized and have great potential for application in nanoelectronics. Similar to the 2D graphene structures can be based on chromium nitride whose magnetic properties will depend on the coordination number and the number of uncoupled electrons correspondingly.In this work, using PAW method and the gradient corrected density functional GGA-PBE within the framework of generalized Kohn-Sham density functional theory (DFT+U) considering weak dispersion interaction, we have predicted the existence of a chromium nitride mono- and bilayers of (100) and (111) crystallographic surface. It was shown that the monolayers geometry relative to the crystalline phase was changed. The 2D CrN (100) and (111) are perfectly flat. To comparison of the energy stability of two dimensional CrN the relative energy of monolayer formation was calculated. Using spin-polarized calculations we calculate ferromagnetic and antiferromagnetic states. The analysis of electronic structure shows that these materials are ferromagnets with 100 % spin polarization. According to the classical Heisenberg model, the exchange parameter J has been calculated (for monolayer 100). The dependence of the changes in the properties during the transition from mono to bilayers structures was investigated.