The electronic structure of crystalline CdTe, CdO, α-TeO2, CdTeO3 and Cd3TeO6 is studied by means of first principles calculations. The band structure, total and partial density of states, and charge densities are presented. For α-TeO2 and CdTeO3, Density Functional Theory within the Local Density Approximation (LDA) correctly describes the insulating character of these compounds. In the first four compounds, LDA underestimates the optical bandgap by roughly 1 eV. Based on this trend, we predict an optical bandgap of 1.7 eV for Cd3TeO6. This material shows an isolated conduction band with a low effective mass, thus explaining its semiconducting character observed recently. In all these oxides, the top valence bands are formed mainly from the O 2p electrons. On the other hand, the binding energy of the Cd 4d band, relative to the valence band maximum, in the ternary compounds is smaller than in CdTe and CdO.
@article{arxiv.cond-mat/0405700,
title = {Electronic structure of crystalline binary and ternary Cd-Te-O compounds},
author = {Eduardo Ariel Menendez Proupin and Gonzalo Gutierrez and Ernesto Palmero and J. L. Peña},
journal= {arXiv preprint arXiv:cond-mat/0405700},
year = {2009}
}
Comments
13 pages, 15 figures, 2 tables. Accepted in Phys Rev B