Elastic stability, electronic structure and optical properties of PtN2 with pyrite and fluorite structures

We present the results of a theoretical study of the structural and optoelectronic properties of PtN2, using the full-potential linearized muffin-tin orbital method (FP-LMTO). In this approach, the local density approximation (LDA) is used for the exchange correlation potential. The calculated total energy allowed us to investigate several structural properties in particular the lattice constant, bulk modulus, pressure derivative of bulk modulus. The phase stability was determined from total energy calculations for both the pyrite (C2) and fluorite (C1) phases. A numerical first-principles calculation of the elastic constants was used to calculate C-11, C-12 and C-44. We estimated the Debye temperature of PtN2 from the average sound velocity. Band structure, density of states, band gap pressure coefficients and effective masses are also given. On the other hand, an accurate calculation of linear optical functions (the dielectric function, refraction index and reflectivity R(omega)) is performed in the photon energy range up to 13.5 eV. The results obtained are compared with other calculations and experimental measurements. (C) 2008 Elsevier B.V. All rights reserved.