Structural parameters, electronic structures, elastic stiffness and thermal properties of M_2PC (M=V, Nb, Ta)

摘要

Using pseudo-potential plane-wave method based on the density functional theory in conjunction with the generalized gradient approximation, structural parameters, electronic structures, elastic stiffness and thermal properties of M_2PC, with M=V, Nb, Ta, were studied. The optimized zero pressure geometrical parameters are in good agreement with the available results. Pressure effect, up to 20 GPa, on the lattice parameters was investigated. Electronic properties are studied throughout the calculation of densities of states and band structures. The elastic constants and their pressure dependence were predicted using the static finite strain technique. We performed numerical estimations of the bulk modulus, shear modulus, Youngs modulus, Poissons ratio and average sound velocity for ideal polycrystalline M_2PC aggregates in framework of the VoigtReussHill approximation. We estimated the Debye temperature and the theoretical minimum thermal conductivity of M_2PC.