First-principles study of ground state properties of ZrH2

• Published in: Computational materials science Vol. 50; no. 12; pp. 3297 - 3302
• Main Authors: Zhang, Peng, Wang, Bao-Tian, He, Chao-Hui, Zhang, Ping
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2011; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Debye temperature; Elastic constants; Elasticity, elastic constants; Electron density of states and band structure of crystalline solids; Electron states; Electronic structure; Electronics; Exact sciences and technology; Face centered cubic lattice; First-principle calculation; Lattice dynamics; Mathematical analysis; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Other inorganic compounds; Phases; Phonon dispersions; Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Physics; Stability analysis; Zirconium; First-principle calculation; Elastic constants; Electronic structure; Phonon dispersions; Elastic modulus; FCC lattices; Tetragonal lattices; Zirconium hydride; Electron charge distribution; Electronic density of states; Lattice parameters; Covalent bonds; Debye temperature; Phonon dispersion; Valence electron; Density functional method; Generalized gradient approximation; Thermodynamic properties
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2011.06.016

► Mechanical properties of ZrH2 are systematically predicted. ► The main distinction of covalent and ionic chemical bonding nature is determined. ► Dynamical stability of phases of ZrH2 are analyzed by the phonon spectrum. Structural, mechanical, electronic, and thermodynamic properties of fluorite and tetragonal phases of ZrH2 are systematically studied by employing the density functional theory within generalized gradient approximation. The existence of the bistable structure for ZrH2 is mainly due to the tetragonal distortions. And our calculated lattice constants for the stable face-centered tetragonal (fct) phase with c/a=0.885 are consistent well with experiments. Through calculating elastic constants, the mechanically unstable characters of face-centered cubic (fcc) phase and fct structure with c/a=1.111 are predicted. As for fct0.885 structure, our calculated elastic constants explicitly indicate that it is mechanically stable. Elastic moduli, Poisson’s ratio, and Debye temperature are derived from elastic constants. After analyzing total and partial densities of states and valence electron charge distribution, we conclude that the Zr–H bonds in ZrH2 exhibit weak covalent feature. But the ionic property is evident with about 1.5 electrons transferring from each Zr atom to H. Phonon spectrum results indicate that fct0.885 structure is dynamically stable, while the fcc and fct1.111 structures are unstable in accord with the mechanical stability analysis.