First Principles Study of the Structural, Elastic, Electronic and Phonon Properties of CdX_2O_4 (X=A1, Ga, In) Spinel-Type Oxides

摘要

We have performed ab-initio calculations of the structural, electronic, elastic and dynamical properties for the spinel compounds CdX_2O_4 (X=Al, Ga, In) using the plane wave pseudo-potential method within the generalized gradient approximation (GGA). The calculated lattice parameters, elastic constants for these compounds are in good agreement with the previous calculated values. The computed direct band gaps of CdAl_2O_4, CdGa_2O_4 and CdIn_2O_4 are 2.90 eV, 1.92 eV and 1.16 eV, respectively. The lattice vibrations were calculated by direct method. The calculated phonon dispersion curves show that all compounds are dynamically stable in the spinel structure.