First-principles LCAO study of phonons in NiWO4

Abstract

Abstract:The electronic, structural and phonon properties of antiferromagnetic wolframite-type NiWO 4 have been studied using first-principles spin-polarized LCAO calculations based on the hybrid Hartree-Fock (HF)/density functional (DFT) scheme. The influence of different percentages of HF contribution, i.e. different correlation strength, on the structure and phonon frequencies has been investigated and compared with the available experimental data. PACS

Synchrotron-based far-infrared spectroscopy of nickel tungstate

“…To interpret infrared spectra, the first-principles LCAO calculations of the phonon frequencies in ZnWO 4 and CoWO 4 were performed using the direct (frozen phonon) method by the CRYSTAL09 code [28], whereas the results for NiWO 4 were taken from our work [29]. The accuracy in the evaluation of the Coulomb and exchange series was controlled by a set of tolerances, set at 10 −8 , 10 −8 , 10 −8 , 10 −8 , 10 −16 , to provide high numerical accuracy.…”

UV-VUV synchrotron radiation spectroscopy of NiWO4

“…The photoluminescence and excitation spectra were interpreted using the results of the first-principles LCAO calculations [22] and the local structural information from the Ni(Zn) K-edge and W L 3 -edge x-ray absorption spectroscopy studies.…”

“…The interpretation of the excitation spectra can be done using the electronic band structure diagram calculated for whereas tungsten 5d-states and nickel 3d(e g ↓)-states contribute largely into the bottom of conduction band [22].…”

“…These applications are tightly connected to its electronic structure being scarcely studied in the past. The electronic band structure of NiWO 4 was calculated recently using first-principles spin-polarized periodic linear combination of atomic orbitals (LCAO) method in [22]. The photoluminescence properties of NiWO 4 powder and sol-gel derived NiWO 4 films, calcined above 600°C, were investigated at room temperature under pulsed Xenon discharge lamp excitation in [23], indicating the presence of a broad blue-green (2.07-3.54 eV) photoluminescence band.…”

“…This experimental set-up is a unique tool for investigations of different types of wide band gap materials [24][25][26][27][28][29][30][31][32][33]. The interpretation of the photoluminescence and excitation spectra is given based on the comparative analysis with isomorphous ZnWO 4 tungstate [32] and using the results of LCAO calculations [22] and the Ni(Zn) K-edge and W L 3 -edge x-ray absorption spectroscopy studies.…”