LAUSR

Abstract Employing the Projector Augmented Wave (PAW) and all-electron Full-Potential Linealized Augmented Plane-Wave (FP-LAPW) methods with the Generalized Gradient Approximation (GGA), we have investigated the electronic band structure (EBS) and densities of states (DOS) of YGa2, crystallizing in the hexagonal AlB2-type structure with space group P6/mmm. Further, we have evaluated for the first time dielectric and optical properties of this compound. Noticeable anisotropy in YGa2 has been observed in the frequency-dependent dielectric functions and other optical quantities for the photon waves polarized along the c and ab-plane. On the basis of a comparison of EBS, DOS and frequency dependencies of optical quantities, we have interpreted the spectrum structures as the results of the intraband and interband transitions for energies below 15 eV and the core level excitations for energies beyond 22 eV. We have found several similarities of the optical properties to those of superconducting MgB2 but clear distinctions to those of nonsuperconducting AlB2.