Вид документа : Статья из журнала Шифр издания : 54/E 43 Автор(ы) : Novikov D. L., Gubanov V. A., Zubkov V. G., Freeman A. J. Заглавие : Electronic structure and electron-phonon interactions in layered LixNbO2 and NaxNbO2 Место публикации : Physical Review B: Condensed Matter. - 1994. - V. 49, N 22. - С. 15830-15835. - ISSN 0163-1829. - ISSN 0163-1829 ББК : 54 Предметные рубрики: ХИМИЧЕСКИЕ НАУКИ Ключевые слова (''Своб.индексиров.''): химия--lixnbo2--naxnbo2--оксониобат лития--оксониобат натрия--структура электронная--электронная структура--электронно-фононное взаимодействие--взаимодействие электронно-фононное Аннотация: Structural, luminescence, and electronic properties of the family of alkaline metal-strontium cyclotetravanadates M2Sr(VO3)4, M=Na, K, Rb, and Cs have been characterized by means of elemental analyses, x-ray powder diffraction, neutron diffraction, electron diffraction, infrared, Raman, photo, x rays, pulse cathode beam excitation, x-ray photoelectron spectroscopy and band structure calculations. The M2Sr (VO3)4 system have tetragonal structures Na-, K-, Rb-P4/nbm and Cs-P4/mmm, with a=10.63449(4), 10.94106(6), 11.08889(8), 7.9183(3) and c=4.96205(4), 5.31600(4), 5.46682(8), 5.5778(3) Å, respectively. The main structural feature of M2Sr(VO3)4 is tetracyclic [V4O12] units. When going from Na2Sr(VO3)4 to Cs2Sr(VO3)4 do the coordination polyhedron around the alkaline metal change continuously from an octahedron to a hexagonal prism and that around the strontium from a square antiprism to a square prism. The hybridized O 2p-V 3d states of tetracyclic [V4O12] units have a dominant influence on the electronic structure of these compounds. All M2Sr(VO3)4 are semiconducting with a decreasing LDA band gap (Ea) from 2.02 for Na2Sr(VO3)4 to 1.56 eV for Cs2Sr(VO3)4 Доп.точки доступа: Novikov, D. L.; Новиков Дмитрий Леонидович; Gubanov, V. A.; Губанов Владимир Александрович; Zubkov, V. G.; Зубков Владимир Георгиевич; Freeman, A. J.