Eur. Phys. J. B 60, 463-468 (2007)
https://doi.org/10.1140/epjb/e2008-00007-3

First-principles study of the optical properties of PbFX (X = Cl, Br, I) compounds in its matlockite-type structure

¹ Institute of Physical Biology-South Bohemia University, Institute of System Biology and Ecology-Academy of Sciences, Nove Hrady 37333, Czech Republic
² Physics Department, Faculty of Science and Engineering, University of M'sila, 28000 M'sila, Algeria

Corresponding author: ^a charifi_z@yahoo.fr

Received: 26 March 2007
Revised: 4 November 2007
Published online: 16 January 2008

Abstract

We present the results of the ab initio theoretical study of the optical properties for PbFX (X = Cl, Br, I) compounds in its matlockite-type structure using the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2K code. We employed generalized gradient approximation (GGA), which is based on exchange-correlation energy optimization to calculate the total energy. Also we have used the Engel-Vosko GGA formalism, which optimizes the corresponding potential for band structure calculations. Our calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at Z resulting in a direct energy gap. We present calculations of the frequency-dependent complex dielectric function ε( ω) and its zero-frequency limit ε₁ ( 0 ). We find that the values of ε₁ ( 0 ) increases with decreasing the energy gap. The reflectivity spectra and absorption coefficient has been calculated and compared with the available experimental data. The optical properties are analyzed and the origin of some of the peaks in the spectra is discussed in terms of the calculated electronic structure.