X-ray spectra and electronic structure of 3C SiC and BN based solid solutions

The local coherent potential approximation is used in the framework of mult iple-scattering theory to calculate the electronic energy structure of soli d solutions of silicon carbide Si1-xCRx and boron nitride BN1-xRx and B1-xN Rx (x = 0-0.75, R = C, Al, Ti) in a diamond-like modification. The total an d partial densities of states are calculated for each atom in the solid sol utions. The crystal potential is evaluated in an MT approximation. The latt ice parameter is determined by Vegard's rule. The electronic energy structu res of the solid solutions are compared with each other and with binary ana logs in the framework of one approximation. The calculated partial densitie s of states are compared with the experimental X-ray spectra of silicon in the compounds. The calculation of the partial charges of atoms at the top o f the valence band showed that the charge transfer (0.35 e) front boron to nitrogen in binary 3C BN changes sign in B0.75NC0.25. In the latter system, nitrogen donates 0.19 e to boron, and carbon acts as a donor for the elect ronic configurations of boron and nitrogen. An electronic structure analysi s of the solid solutions indicates that the quasicore resonance states inhe rent in the binary compounds are delocalized, probably because of the weake ning of chemical binding in the solid solutions.