Structural and Thermodynamic Properties of Wurtzitic Boron Nitride from First-Principle Calculations

Using ab initio plane-wave pseudopotential density functional theory method, we have studied the structural and thermodynamic properties of the wurtzite boron nitride (w-BN). Through the quasi-harmonic Debye model, in which the phononic effects are considered, the dependencies of the normalized lattice parameters a/a₀ and c/c₀, the axial ratio c/a, and the normalized primitive cell volume V/V₀ on pressure P and temperature T are investigated. Furthermore, the Debye temperature Θ, the variation of thermal expansion α, as well as the heat capacity C_V as functions of P and T are studied systematically.