Electronic structures of electron-doped SrTiO 3Ϫ␦ and Sr 1Ϫx La x TiO 3 have been investigated within the ab initio band-structure approach using a supercell containing eight basic units. A small amount of electron doping is found to drive SrTiO 3 metallic, with the Fermi level moving into the conduction band in both the systems. Clustering of oxygen vacancies in the case of SrTiO 3Ϫ␦ gives rise to distinct non-rigid-band-like evolution of the electronic structure, trapping doped charge carriers in midgap states; similar effects are not observed for Sr 1Ϫx La x TiO 3 , explaining the difference in the Hall measurements of these two closely related compounds.
We analyze the electronic structure of group II-VI semiconductors obtained within LMTO approach in order to arrive at a realistic and minimal tight binding model, parameterized to provide an accurate description of both valence and conduction bands. It is shown that a nearest-neighbor sp 3 d 5 model is fairly sufficient to describe to a large extent the electronic structure of these systems over a wide energy range, obviating the use of any fictitious s * orbital. The obtained hopping parameters obey the universal scaling law proposed by Harrison, ensuring transferability to other systems. Furthermore, we show that certain subtle features in the bonding of these compounds require the inclusion of anion-anion interactions in addition to the nearest-neighbor cation-anion interactions.PACS 71.20.Nr
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.