Newly synthesized MAX phase Zr(2)SeC: DFT insights into physical properties towards possible applications

A DFT study of the synthesized MAX phase Zr(2)SeC has been carried out for the first time to explore its physical properties for possible applications in many sectors. The studied properties are compared with prior known MAX phase Zr(2)SC. The structural parameters (lattice constants, volume, and atomic positions) are observed to be consistent with earlier results. The band structure and density of states (DOS) are used to explore the metallic conductivity, anisotropic electrical conductivity, and the dominant role of Zr-d states to the electrical conductivity at the Fermi level. Analysis of the peaks in the DOS and charge density mapping (CDM) of Zr(2)SeC and Zr(2)SC revealed the possible variation of the mechanical properties and hardness among them. The mechanical stability has been checked using elastic constants. The values of the elastic constants, elastic moduli and hardness parameters of Zr(2)SeC are found to be lowered than those of Zr(2)SC. The anisotropic behavior of the mechanical properties has been studied and analyzed. Technologically important thermodynamic properties such as the thermal expansion coefficient (TEC), Debye temperature (Θ(D)), entropy (S), heat capacity at constant volume (C(v)), Grüneisen parameter (γ) along with volume (V) and Gibbs free energy (G) are investigated as a function of both temperature (from 0 to 1600 K) and pressure (from 0 to 50 GPa). Besides, the Θ(D), minimum thermal conductivity (K(min)), melting point (T(m)), and γ have also been calculated at room temperature and found to be lowered for Zr(2)SeC compared to Zr(2)SC owing to their close relationship with the mechanical parameters. The value of the Θ(D), K(min), T(m), and TEC suggest Zr(2)SeC as a thermal barrier coating material. The optical properties such as dielectric constant (real and imaginary part), refractive index, extinction coefficient, absorption coefficient, photoconductivity, reflectivity, and loss function of Zr(2)SeC are computed and analyzed to reveal its possible applications.