東京大学 · 材料科学
三ツ口徹安教授の研究室は、電子エネルギー損失スペクトロスコピー(ELNES)とX線吸収端近隣構造(XANES)を第一原理計算を用いて高精度に予測・解釈する研究を展開しています。特に、酸化物半導体や窒化物半導体をはじめとする幅帯ギャップ材料の電子状態や化学環境の微細な違いを解明しており、核殻効果や局所電子状態の影響を精密に取り入れた理論的アプローチが特徴です。実験と理論の一致を高めるために、大規模スーパーセルや励起状態におけるポテンシャルの修正を駆使し、材料の電子構造と物性の関係を解明しています。
Figures are computed from collected data and may differ slightly.
Theoretical calculations of electron energy-loss near-edge structure (ELNES) and x-ray absorption near-edge structure (XANES) of selected wide-gap materials including ${\text{TiO}}_{2}$, AlN, GaN, InN, ZnO, and their polymorphs are performed using a first-principles method. Calculations of 39 $K$ and ${L}_{3}({L}_{2,3})$ edges are made using large supercells containing 72 to 128 atoms. A core hole is included in the final state, and the matrix elements of the electric dipole transition between t
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnodic Oxidation Studies of N,N-Dimethylaniline. I. Voltammetric and Spectroscopic Investigations at Platinum ElectrodesT. Mizoguchi and R. N. AdamsCite this: J. Am. Chem. Soc. 1962, 84, 11, 2058–2061Publication Date (Print):June 1, 1962Publication History Published online1 May 2002Published inissue 1 June 1962https://pubs.acs.org/doi/10.1021/ja00870a009https://doi.org/10.1021/ja00870a009research-articleACS PublicationsRequest reuse permissionsArticle
Classical magnetic dipolar interactions can make significant contributions to magnetic anisotropy in amorphous ferrimagnetic alloys with slight structural anisotropies on either atomic or microstructural scales. Simple expressions have been derived for this magnetic anisotropy in terms of structural anisotropy parameters, p, V, and Δx. For an alloy with atomic-scale structural anisotropy (pair ordering), p is a measure of alignment of unlike nearest-neighbor pairs. For an alloy with aligned elon
Amorphous films of composition ${\mathrm{Gd}}_{0.37}$${\mathrm{Al}}_{0.63}$ are found to exhibit a transition to a spin-glass state below 16 K. The magnetic properties show thermal hysteresis and relaxation below the spin-glass transition. The susceptibility maximum at 16 K, when measured in dc fields \ensuremath{\le}10 Oe, sharpens into an asymmetric cusp, consistent with the Edwards-Anderson picture of the transition as one into a random, but rigid, state. Using the theory of Sherrington and K
Spectral features, chemical shifts, and absolute thresholds of electron energy loss near-edge structure (ELNES) and x-ray absorption near-edge structure (XANES) for selected compounds, i.e. TiO(2) (rutile), TiO(2) (anatase), SrTiO(3), Ti(2)O(3), Al(2)O(3), AlN and β-Ga(2)O(3), were calculated by a plane wave pseudopotential method. Experimental ELNES/XANES of those compounds were well reproduced when an excited pseudopotential, which includes a core hole, was used. In addition to the spectral fe
First-principles molecular orbital calculations using model clusters are made in order to reproduce and interpret experimental electron-energy-loss near-edge structure and near-edge x-ray absorption fine structure of MgO at Mg K, ${L}_{2,3}$ and O K edges. Ground-state calculations using a model cluster composed of 125 atoms and by a band-structure method are in good agreement, but they do not reproduce the experimental spectra satisfactory. They are well reproduced only by the cluster calculati
The present state of knowledge and understanding of the basic magnetic properties of amorphous alloys is reviewed. It covers magnetic moments, exchange interaction, temperature dependence of the magnetization and anisotropy for two categories: metal‐metalloid and rare earth‐transition metal amorphous alloys. Some apparent discrepancies in our present knowledge are pointed out.
Electron energy loss near-edge structures (ELNES) and first-principles band structure calculations were combined in order to identify native defects which are segregated by heat treatments at the vicinity of SrTiO3 grain boundary (GB). Spectral differences between the bulk and the vicinity of GB mainly appear around the second peak of OK ELNES. The spectral differences can be reproduced by calculating the theoretical OK ELNES from the first-nearest-neighbor oxygen to a Sr vacancy. It is therefor
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