TO THE CRYSTALLOCHEMICAL PROPERTIES OF CHALCOPYRITE COMPOUNDS

A.A. Lavrentyev, B.V. Gabrelian, I.Ya. Nikiforov

Don State Technical University, Rostov-on-Don, Russia

The electron structure of some chalcopyrites I-III-VI2 (where I=Cu,Ag; III=Ga,In; and VI=S,Se) has been calculated in the frame of the full multiple scattering theory. The crystallographic parameters including the tetragonal deformation and anion displacement have been determined using the generalized formula of Jaffe and Zunger (Phys.Rev.B 29, 1882 (1984)) with the covalent tetrahedral Pauling radii. The crystal potential has been calculated with the code FEFF7. The calculated electron densities of p-states of sulfur are in a good agreement with the x-ray absorption spectra (XANES) of S obtained with Johann spectrograph and literature data. So the chemical bonding in the ternary compounds with the chalcopyrite structure is mostly covalent one. Using the predicted structural parameters found according to the same cheme for the possible chalcopyrite-structure semiconductor the ternary analog to diamond BeCN2 the total density of electron states of the valence and unoccupied bands has been calculated. The calculated gap for this compound is about 8.5 eV.