Features of forming the electronic structure at synthesis of Ti$_{2}$AlC, Ti$_{2}$AlN, Ti$_{2}$SiC, and Ti$_{2}$SiN compounds

The electronic structure and total energy of the Ti$_{2}$AlC, Ti$_{2}$AlN, Ti$_{2}$SiC, and Ti$_{2}$SiN compounds are investigated by methods of the density functional theory and pseudopotentials. Electron state density curves have been constructed for crystal systems and for systems differing in order. It has been shown that even in completely disordered systems there is a qualitative similarity of the electronic structure with an electronic structure of the respective crystalline compounds. This similarity is further enhanced as the degree of ordering increases. The total energy of the studied systems grows with increasing disorderance in about the same way for all studied systems except Ti$_2$SiC. In the latter case, it turns out to be much more sensitive to the degree of disordering, which seems to be due to the greater role of the covalent component of interatomic bonds.