Font Size:
Electronic and optical properties of the LiZnX (X = P, As and Sb) filled-tetrahedral compounds
Last modified: 2018-07-22
Abstract
The structural, electronic and optical properties of the LiZnP, LiZnAs and LiZnSb filled-tetrahedral compounds were explored using the full-potential (Linearized) augmented plane-wave plus local orbitals method (FP-(L)APW+lo)). Calculated structural parameters, including the lattice constant (a), bulk modulus (B) and its pressure derivative (B'), for the considered compounds using both the local density (LDA) and generalized gradient approximations (GGA) are consistent with the available data in the scientific literature. As the density functional theory with the common LDA and GGA underestimates the band gap, we have used a newly developed functional that is able to accurately describe the electronic structure of semiconductors, namely the TranBlaha-modified BeckeJohnson potential. The three investigated compounds demonstrate semiconducting behavior with indirect band gap (ΓX) ranging from about 1.41 to 1.90 eV. The charge-carrier effective masses were evaluated at the topmost valence band and at the bottommost conduction band. The evolution of the value and nature of the energy band gap under pressure effect was also investigated. Optical functions of the tile compounds, including the dielectric function , refractive index , extinction coefficient , reflectivity , absorption coefficient and electron energy-loss function , were calculated for the energy range 0-20eV. The origins of the peaks and structures in the optical spectra were determined in terms of the calculated energy band structures