Theretical study of structural, electronic, optical and elastic properties of the ternary zintl compounds A2CuAs(A=Na,K)

Abstract

The ground state physical properties of Zintl compounds NazCuAs and K2CuAs have been investigated. Using the GGA-PBE approximation of density functional theory (DFT) as implemented in the CASTEP code. The calculated equilibrium geometry agrees well with its experimental counterpart. The computed elastic stiffness constants were used to investigate the whole elastic behavior of the compounds under consideration. According to the obtalned results, both materlals will show high extend of elastic anisotropy; they are soft and easily compressible. The energy band dispersion indicates that they are indirect narrow gap semiconductors. Mulliken charges analysis show that there is a significant covalent interaction between Cu and As, as well as lonic interaction of A-Cu contact. Many important optical properties have been computed throughout a broad energy range. According to the obtained results, both materials are active in the UV spectral domain and transparent in the IR.