Thermodynamic and mechanical properties of lanthanum–magnesium phases from density functional theory

摘要: Abstract Thermodynamic and mechanical properties of the six known phases in La–Mg phase diagram, viz. LaMg, LaMg2, LaMg3, La5Mg41, La2Mg17, LaMg12, their elemental antecedents, Mg La, are computed with density functional theory (DFT) using PBE PBEsol exchange-correlation functionals. Phase stability analyses show that both LaMg2 La5Mg41 metastable at low temperatures which is consistent experiments vibrational spectra. We generalize an existing approach for computing crystallographic dependence Young's modulus Poisson's ratio, presently limited to cubic systems, address any space group symmetry 0 K elasticity tensor components (Cij) from DFT. Isothermal isentropic Cij(T) quasiharmonic approximation (QHA) as linear thermal expansion compounds, average non-cubic bulk modulus, constant pressure heat capacity. A critical comparison theoretical results functionals made available experimental data.