P-D HYBRIDIZATION OF THE VALENCE BANDS OF AGXCU1-XGASE2 COMPOUNDS

Abstract

Polycrystalline compounds of Ag(x)Cu(1-x)GaSe2 were grown by the Bridgman method. x was varied from 1.0 to 0.0 at intervals of 0.2. The optical absorption spectra of these six samples were measured using a photoacoustic spectrometer. From these spectra we determined the A, B and C transition energies of Ag(x)Cu(1-x)GaSe2 as functions of the silver concentration x. The transition energies E(A) and E(C) relative to transition energy E(B) were used to obtain both the spin-orbit splitting of the valence bands in a cubic field and the crystal-field splitting of the valence bands in the absence of spin-orbit interaction as functions of x. Furthermore, we estimated the fractional p-like character of the uppermost valence bands for various x, under the assumption that the d levels of Ag and Cu contribute to the spin-orbit splitting according to x.