DFT studies of electronic structure and dielectric properties in layered perovskite _{LaSrAlO 4}

The structural, electronic, dielectric and optical properties of tetragonal _{LaSrAlO 4} are studied in detail using density functional theory calculations. The energy band structures and density of states are predicted by generalized gradient approximation (GGA) and local density approximation (LDA) respectively. The fundamental band gaps of _{LaSrAlO 4} are all indirect by GGA (2.860 eV) and LDA (2.863 eV) calculations. The complex dielectric function was calculated. There are two peaks in the real part _ε1(ω) and three peaks in the imaginary part _ε2(ω). The optical spectra are assigned to the interband transition from O valence to La and Sr conduction bands in the low energy region. In addition, the electron energy-loss spectrum, optical conductivity, reflectivity spectrum, and refractive index, are given to support the potential applications for microwave dielectric ceramics.