Systematics in the optical and electronic properties of the binary lanthanide halide, chalcogenide and pnictide compounds: an overview

The basic optical, electrical and chemical properties of the binary divalent, trivalent and tetravalent lanthanide (Ln= La, . . . , Lu) halides (F, Cl, Br and I), chalcogenides (O, S, Se and Te) and pnictides (N, P, As and Sb) were studied using an empirical model that utilizes the systematic behaviour in the energy difference between the localized 4f n-states, the 5d-derived conduction band and the mp-derived valence band (m = 2, . . . , 5) over the Lanthanide series. As the wide variety in the electrical and optical properties of Ln materials is to a large extent controlled by the energy of these states relative to each other, it is possible to simultaneously predict insulating, semiconducting or metallic behaviour, the nature and magnitude of bandgap energies and the chemical stability of Ln materials as well as valence and valence changes of Ln ions. It can thus be used to predict the basic electronic structure of materials for which no experimental data can be found, and may be a guideline for theoretical modelling. 1 Author to whom any correspondence should be addressed. New Journal of Physics 13 (2011) 093038 1367-2630/11/093038+32$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft