Electronic states of rutile dioxides: RuO2, IrO2, and

Abstract

We studied the metal d and 0 2pderived electronic states of RuO» IrO» Ru065Ir03$02 arid Ru077Ilp 2302 by photoemission spectroscopy with synchrotron radiation. Our data are in qualitative agreement with the Ru02 and Ir02 density-of-states curves calculated by Mattheis, which consist of one d-electron peak and three other major peaks with prevailing 0 2p character. The quantitative agreement is reasonably good for Ru0» while discrepancies exist for the lower-energy states of Ir02. Revelation of these discrepancies, not evident from previous photoemission studies, was made possible by the investigation of mixed Ru02-Ir02 crystals.

Electronic structure of rutile metal dioxides with partially filled d band investigated by LSDA+U method

“…2 compares the calculated total DOS (solid curves) and PE spectra (closed circles) for XO 2 (X ¼ Ti, Cr and Ru), where the PE data are cited from Refs. [10][11][12]. For TiO 2 , the PE spectrum shows no spectral weight at the Fermi surface and is insulating, which is in agreement with our calculations.…”

“…For RuO 2 , there are two bands observed below Fermi level at $1 and $4 eV, respectively. The narrow peak at $1 eV and the broad band at $4 eV below Fermi surface have been ascribed to the hybridization of O2p and Ru4d states [12], which are in agreement with our calculated results.…”

Formation energies of rutile metal dioxides using density functional theory

“…Electron, neutron, and x-ray diffraction experiments have detected a large number of transition-metal dioxides to possess very stable ␤Ј rutile crystal phases. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] In addition, some theoretical studies, at different levels of theory, have confirmed the structural results of the experiments, showing enhanced stability of the rutile phase for most metal dioxides. [20][21][22][23] Rutile oxides are interesting in connection with electrochemical and photoelectrochemical water splitting, [24][25][26][27] and recently the surface redox processes on, e.g., RuO 2 and TiO 2 have been treated using density functional theory ͑DFT͒.…”

Core-Level X-Ray Photoemission Satellites in Ruthenates: A New Mechanism Revealing The Mott Transition

“…The new mechanism of the core-level photoemission satellite can be utilized to reveal the Mott transition phenomenon in various strongly correlated electron systems, especially in nano-scale devices and phase-separated materials. Such a strong electron correlation effect has been considered to be weak in 4d TMCs because 4d orbitals are fairly delocalized, and RuO 2 , for example, is traditionally classified as a band metal [6]. However, recent studies revealed that many ruthenates such as Ca 2−x Sr x RuO 4 [7] and pyrochlores [8,9] have various interesting properties related with the correlation effect among Ru 4d electrons.…”