First-principles calculations of structural and thermodynamic properties of BeB₂ compound

The lattice parameter, bulk modulus and pressure derivative of BeB₂ are calculated by using the Cambridge Serial Total Energy Package (CASTEP) program in the frame of density function theory. The calculated results agree well with the average experimental data and other theoretical results. Through the quasi-harmonic Debye model, the dependences of the normalized lattice parameters a/a_0, c/c₀ and the normalized primitive cell volume V/V₀ on pressure P, the variation of the thermal expansion coefficient \alpha with pressure P and temperature T, as well as the dependences of the heat capacity C_V on pressure P and temperature T are obtained systematically.