First-principles investigation of the structural, dynamical, electronic, and elastic properties of WGe₂ and W₅Ge₃

ABSTRACT

We have investigated the structural, dynamical, elastic, and electronic properties of WGe₂ and W₅Ge₃ compounds in different phases. We have considered the C11_b (tetragonal, space group I4/mmm) and C23 (orthorhombic, space group Pnma) strukturbericht phases for WGe₂ compound and D8₁ (tetragonal, space group I4/mcm), D8_m (tetragonal space group I4/mcm) strukturbericht phases for W₅Ge₃ compound. The structural parameters, formation enthalpies, phonon dispersion curves, elastic constants, mechanical modulus, anisotropic factors, thermal conductivities, and electronic structures have been investigated using generalised gradient approximation within in the plane wave pseudopotential density functional theory. The calculated lattice constants are in a good agreement with the experimental data. The considered phases for WGe₂ and W₅Ge₃ compounds have a metallic character. The results indicated that all phases for compounds are both mechanically stable and dynamically stable except for W₅Ge₃-D8₁. The anisotropy in some mechanical modulus has been investigated using several elastic anisotropy indexes and directional dependence of compressibility, Young’s moduli, shear moduli, and Poisson’s ratio.

KEYWORDS:

• Tungsten germanides
• mechanical properties
• electronic structure
• dynamical properties
• first-principles

Acknowledgements

In this paper, the numerical calculations reported were partially performed at TUBITAK ULAKBIM High Performance and Grid Computing Center and Aksaray University, Science and Technology Application and Research Center.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

E. Bolen http://orcid.org/0000-0001-8171-0757

H. Ozisik http://orcid.org/0000-0002-4011-1720