Technical Report of ISSP Ser. A: Number 3144

Abstract

The 2p core level X-ray Photoemission Spectra (XPS) for a series of Transition Metal (TM) sesquioxides M2O3(M = Ti, V, Cr, Mn, Fe) have been systematically investigated. Theoretical analysis has been made by means of a MO6 cluster model with the full multiplet structure of the M ion and the calculated results of 2pXPS are in good agreement with the experimental data. Moreover, theoretical and experimental investigations of 3p, 3sXPS, valence XPS and Bremsstrahlung Isochroma Spectra (BIS) for Cr2O3 have also been performed and all of these experimental data are satisfactorily reproduced with the cluster model approach. The character of the insulating energy gap of these M2O3 compounds is also studied based on the spectral analysis. It is shown that M2O3 from Ti2O3 to Mn2O3 are classified as the intermediate-type insulator between the Charge Transfer (CT) insulator and the Mott-Hubbard (MH) insulator, and Fe2O3 is classified as the CT insulator.

一連の遷移金属(TM)セスキ酸化物M2O3(M=Ti,V,Cr,Mn,Fe)について2pコア準位X線光電子放出スペクトル(XPS)を体系的に調査した。Mイオンの全多重線構造を持ったMO6クラスター模型を用いて理論解析を行った、2pXPSの計算結果は実験結果と良く一致した。さらに、Cr2O3について3p、3sXPS、価電子XPSおよび制動放射等色スペクトル(BIS)を理論的および実験的に調査した結果、すべての実験データはクラスター模型アプローチで十分に再現できた。M2O3化合物の絶縁エネルギーギャップの特性をスペクトル解析に基づき研究した。Ti2O3からMn2O3までのM2O3は電荷移動(CT)絶縁体とMott-Hubbard(MH)絶縁体の間の中間型絶縁体として分類し、Fe2O3はCT絶縁体として分類した。