Role of local interactions in formation of electronic properties of La2CuO4 type materials

Calculations of electron structure of clusters simulating the volume and the surface of materials based on La2CuO4 are carried out by the method of Xα-discrete variation. It is shown that it is sufficient to consider interactions of the short-range order in order to describe some characteristic electron features of oxide superconductors, in particular, a strong specific response of electron systems for hole formation. This specific feature is typical not only for volume but for the surface if the coordinated surrounding of copper atoms is kept. On the basis of simulation of the initial stage of formation of the interface Cu/La2CuO4 the conclusion that the presence of even separate adsorption copper atoms on the surface is to lead to disappearance of specific features of the electron structure, being characteristic for HTSC-materials in the near-to-the surface layer, is made