Optical and thermal properties of Scanduim chalcogenides: DFT study

Abstract

The full potential linearized augmented plane wave (FP-LAPW) calculations based on
 density functional theory (DFT) is performed to study the structural, electronic, optical
 and thermodynamic properties of Scanduim chalcogenides ScX (X = S, Se, Te) and them
 ternary alloys at equilibrium as well as under pressure. The revised Perdew-Burke-Ernzerhof generalized gradient approximation (GGA) is used to calculate the structural properties. The electronic and optical properties are calculated employing the GGA and the modified Becke-Johnson (mBJ) approaches. Moreover, the calculated lattice parameters agree well with the experiment results. The NaCl structure (B1) of the scandium chalcogenides undergo under pressure a structural phase transition to CsCl-type (B2) and ZnS-type (B3). The binary and ternary alloys indicate a metallic behavior using GGA and mBJ scheme. The interband contribution to the optical properties is investigated and the parameters ε1(ω), ε2(ω) and n(ω) are calculated. A Quasi-harmonic Debye model is applied to calculate the thermal properties.