First-principles calculations to investigate structural, electronic, optical and elastic properties of α-Ca3N2

Abstract

The optoelectronic industry, which has become a cornerstone, requires a semiconductor compound to function as a sustainable and green energy source. In this connection, the present study provides a systematic approach to examine the electronic and optical properties of α-Ca3N2 using the linear combination of atomic orbitals method. The xc-functional BECKE-PBE gives the best results for electronic properties by describing the band gap correctly. The dispersion curve shows that α-Ca3N2 is a semiconductor with an indirect band gap of 1.33 eV along the H-Γ direction. Effective masses of electrons and holes are calculated at the peak of the lowest conduction band and highest valence band, along the Γ- direction. Calculation for optical properties has been performed using coupled-perturbed Hartree-Fock scheme for static values and phonon spectrum calculations are performed for dynamic dielectric functions. Further, frequency dependent electron loss function and reflectivity are determined from the dielectric functions. The elastic constants are estimated and elastic moduli are determined. Bulk modulus of 80.6 GPa and Poisson’s ratio of 0.275 reveals that α-Ca3N2 is a hard and ductile material. The characteristic properties of α-Ca3N2 make it a suitable candidate for optoelectronic applications.