Comparison of Electronic and Optical Properties of the α and κ Phases of Alumina Using Density Functional Theory

S. J. Mousavi；M. R. Abolhassani；S. M. Hosseini；S. A. Sebt

Chinese Journal of Physics

47卷6期（2009 / 12 / 01）

862 - 873

英文

κ-Al2O3 is α metastable phase of alumina. We have investigated the electronic structure and optical properties of κ-Al2O3 by a first-principles calculation in the framework of density functional theory (DFT) and the full potential linearized augmented plane wave (FP-LAPW) with three different potentials: the generalized gradient approximation (GGA), the local density approximation (LDA), and the Engle-Vosco approximation (EVA). The results were compared with the stable phase α-Al2O3. Our calculated value for the direct band gap of α-Al2O3 is 7.2 eV, which is very close to its experimental measurement. A direct band gap of 5.95 is obtained for κ-Al2O3 which is about 1.25 eV smaller than that of α-Al2O3. The calculated optical reflectivity, optical conductivity, and electron energy loss spectrum for α- and κ-Al2O3 are similar on the whole, and for α-Al2O3 are in excellent agreement with the experimental measurements.