Electronic and optical properties of the orthorhombic compounds PdPX (X = S and Se)

We have investigated the structural, electronic and optical properties of the orthorhombic layered compounds PdPX (X = S and Se). The calculations are based on the total-energy calculations within the full-potential augmented plane-wave plus local orbitals (FP-LAPW + lo) method. We have used the local density approximation for the exchange and correlation potential. The structural properties are determined through the total energy minimization and inter atomic forces calculations. The obtained results agree well with the measured ones. Our calculations show that these compounds are indirect-gap semiconductors. The calculated anisotropic frequency dependent dielectric functions, reflectivity, refractive index and absorption spectra are obtained and discussed.