Investigating the electronic structure of fluorite-structured oxide compounds: comparison of experimental EELS with first principles calculations

• Published in: Journal of physics. Condensed matter Vol. 24; no. 29; p. 295503
• Main Authors: Aguiar, J A, Ramasse, Q M, Asta, M, Browning, N D
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 25.07.2012; Institute of Physics
• Subjects: Computation; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Electron density of states and band structure of crystalline solids; Electron energy loss spectra; Electron energy loss spectroscopy; Electron states; Electrons; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Least squares method; Least-Squares Analysis; Mathematical analysis; Oxides; Oxides - chemistry; Physics; Quantum Theory; Scanning electron microscopy; Semiconductor compounds; Spectra; Spectroscopy, Electron Energy-Loss; Cross correlations; Electron energy loss spectra; Electronic structure; Zirconium oxide; Non linear model; Density functional method; Fluorite structure; Scanning transmission electron microscopy; Least square fit; Uranium oxide; Cerium oxide; APW calculations
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/24/29/295503

Energy loss spectra from fluorite-structured ZrO2, CeO2, and UO2 compounds are compared with theoretical calculations based on density functional theory (DFT) and its extensions, including the use of Hubbard-U corrections (DFT + U) and hybrid functionals. Electron energy loss spectra (EELS) were obtained from each oxide using a scanning transmission electron microscope (STEM). The same spectra were computed within the framework of the full-potential linear augmented plane-wave (FLAPW) method. The theoretical and experimental EEL spectra are compared quantitatively using non-linear least squares peak fitting and a cross-correlation approach, with the best level of agreement between experiment and theory being obtained using the DFT + U and hybrid computational approaches.