Electronic structure, optical properties and Compton profiles of RuO2: Performance of PBEsol exchange-correlation approximation

We present first ever electron momentum density of RuO2 using 20 Ci Cs-137 (661.65 keV) Compton spectrometer at a resolution (Gaussian FWHM) of 0.34 a.u. The experimental Compton profile (CP) has been compared with the theoretical profiles computed using linear combination of atomic orbitals (LCAO) within framework Hartree-Fock scheme and of density functional theory. Comparison of theoretical and experimental CPs demonstrates usefulness of revised functional of Perdew-Burke-Ernzerhof (so called PBEsol) in computing the electronic properties of RuO2. The energy bands and density of states of RuO2 are also reported using LCAO and full potential linearized augmented plane wave (FP-LAPW) method within PBEsol approximation. The complex dielectric functions computed using FP-LAPW method are explained in terms of transitions within energy bands. Our results for dielectric functions show a good agreement with the available experimental data and confirm the Drude like behavior of RuO2. The Fermi surface structure and reflectivity spectra computed using FP-LAPW method are found to be in tune with the available measurements. (C) 2015 Elsevier B.V. All rights reserved.