Structural, electronic and nonlinear optical properties of B3 and B20 compounds: A first-principles investigation within the LDA, GGA and modified Becke–Johnson exchange potential plus LDA

Abstract

The structural, electronic, and nonlinear optical properties of 111 crystals belonging to structural types B3 (84 crystals) and B20 (27 crystals) have been investigated by first-principles calculations using the full-potential linearized augmented plane wave (FP-LAPW) method in the framework of density functional theory. Calculations of the electronic band structure and nonlinear optical properties were performed using local-density approximation (LDA), generalized gradient approximation (GGA), and a combination of modified Becke—Johnson exchange potential plus LDA (mBJ+LDA) for exchange–correlation potential. Equilibrium lattice constant a0, bulk modulus B0, first pressure derivative B′ of the bulk modulus, band gaps Eg, and second-order nonlinear susceptibility tensor components |χ123| at 0eV and at 1.064 and 10.6μm wavelengths are presented. The obtained results are compared to available experimental and theoretical (computational) data. A correlation between the |χ123| tensor component data arrays and the distributions of crystal structures with respect to their degree of pseudoinversion is analyzed.