Hydrostatic pressure effects on the structural, elastic and thermodynamic properties of the complex transition metal hydrides A₂OsH₆ (A = Mg, Ca, Sr and Ba)

ABSTRACT

We report a systematic first-principles density functional theory study on the pressure dependence of the structural parameters, elastic constants and related properties and thermodynamic properties of the complex transition metal hydrides Mg₂OsH₆, Ca₂OsH₆, Sr₂OsH₆ and Ba₂OsH₆. The calculated structural parameters are in excellent agreement with the existing data in the scientific literature. The single-crystal elastic constants and related properties were predicted using the stress–strain method. The elastic moduli of the polycrystalline aggregates were evaluated via the Voigt–Reuss–Hill approach. The dependences of the lattice parameter, bulk modulus, volume thermal expansion coefficient, isobaric and isochoric heat capacity and Debye temperature on the pressure and temperature, ranging from 0 to 15 GPa and from 0 to 1000 K, respectively, were investigated using the quasi-harmonic Debye model in combination with first-principles calculations.

KEYWORDS:

• Complex transition metal hydrides
• first-principles calculation
• pressure effect
• elastic constants
• thermodynamic properties

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Y. Al-Douri http://orcid.org/0000-0002-5175-6372

Additional information

Funding

The authors (A. Bouhemadou and S. Bin-Omran) extend their appreciation to the International Scientific Partnership Program ISPP at King Saud University for funding this research work through JSPP# 0025.