Influence of orbital contributions to the valence band alignment of Bi2O3, Fe2O3, BiFeO3, and Bi0.5Na0.5TiO3
Influence of orbital contributions to the valence band alignment of Bi2O3, Fe2O3, BiFeO3, and Bi0.5Na0.5TiO3
复制标题
DOI：
10.1103/physrevb.88.045428
复制
发表时间：
2013-07-17
影响因子：
3.7
通讯作者：
Albe, Karsten
中科院分区：
文献类型：
--
作者：
Li, Shunyi;Morasch, Jan;Albe, Karsten
使用原位 RuO2 沉积的光电子能谱研究了 Bi2O3、Fe2O3、BiFeO3、Bi0.5Na0.5TiO3 和高功函数金属 RuO2 之间界面的形成。导出肖特基势垒高度，并且所研究材料的价带最大能量相对于彼此以及其他功能氧化物（如 SrTiO3 和 PbTiO3）对齐。与大量氧化物相比，能带排列遵循系统趋势，并且可以根据 Fe 3d 和 Bi 6s/6p（孤对）轨道对价带最大值附近电子态的贡献来理解。结果表明，价带最大值很大程度上取决于阳离子的局部环境，这使得可以根据其母体二元化合物估计具有多个阳离子的氧化物的价带最大能量。 BiFeO3 的高价带最大值与报道的受主掺杂材料的 p 型传导一致，而高导带最小值使得 n 型传导不太可能。
The formation of an interface between Bi2O3, Fe2O3, BiFeO3, Bi0.5Na0.5TiO3, and the high work function metallic RuO2 is studied using photoelectron spectroscopy with in situ RuO2 deposition. Schottky barrier heights are derived and the valence band maximum energies of the studied materials are aligned with respect to each other as well as to other functional oxides like SrTiO3 and PbTiO3. The energy band alignment follows systematic trends compared to a large number of oxides, and can be understood in terms of the contribution of Fe 3d and Bi 6s/6p (lone pair) orbitals to electronic states near the valence band maximum. The results indicate that the valence band maxima are largely determined by the local environment of the cations, which allows to estimate valence band maximum energies of oxides with multiple cations from those of their parent binary compounds. The high valence band maximum of BiFeO3 is consistent with reported p-type conduction of acceptor doped material, while the high conduction band minimum makes n-type conduction unlikely.