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

摘要

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 1000 K, the relationship between bulk modulus B and pressure at different temperatures are worked out. The pressure dependences of heat capacity Cv and thermal expansion α atvarious 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.