First-principles calculations of elasticity and thermodynamic properties of LaNi₅ crystal under pressure

This paper investigates the equilibrium lattice parameters, heat capacity, thermal expansion coefficient, bulk modulus and its pressure derivative of LaNi₅ crystal by using the first-principles plane-wave pseudopotential method in the GGA-PBE generalized gradient approximation as well as the quasi-harmonic Debye model. The dependences of bulk modulus on temperature and on pressure are investigated. For the first time it analyses the relationships between bulk modulus B and temperature T up to 1000K, the relationship between bulk modulus B and pressure at different temperatures are worked out. The pressure dependences of heat capacity C_v and thermal expansion α at various temperatures are also analysed. Finally, the Debye temperatures of LaNi₅ at different pressures are successfully obtained. The calculated results are in excellent agreement with the experimental data.