XANES analysis of ZnSe ternary compounds with transition metals (TM): experimental and theoretical LMTO studies

Experimental studies of X-ray absorption near edge structure (XANES) in ter nary compounds of ZnSe with transition metals (TM) (where TM=Ti, V, Cr, Co and Ni) for Se and Zn K edges have been carried out and compared with the a bsorption edge of pure ZnSe. This comparison for Se and Zn K edges shows si milar behaviour of these edges, respectively, versus number of 3d electrons in the TM. These results were compared with the electron densities of stal es (DOS) in the conduction band obtained from theoretical LMTO calculations for an ordered ferromagnetic phase of ZnTMSe (25% TM content). In particul ar the p-like DOS for ZnMnSe, ZnFeSe and other ZnTMSe around Zn and Se ions were compared in an energy range close to the Fermi level. For the Se edge , very good agreement between theoretical estimates and the experimental an alysis was obtained. It has been shown that for both Se and Zn absorption e dges the addition of TM to the pure ZnSe host crystal causes additional fea tures, apart from the interaction with the valence band, in the forbidden g ap of ZnSe (deep donors and acceptor states), as well as an additional cont ribution in the conduction band. The energy positions of these features dep end on the number of TM 3d electrons and can be composed in two sequences T i, V, Cr, and Ni, Co, Fe, respectively. The hybridized contribution of Mn 3 d states around Se and Zn ions are immersed deeper in the conduction band t han for other TMs. (C) 1999 Elsevier Science S.A. All rights reserved.