通过X射线吸收光谱研究金属间化合物CeCo2纳米薄膜的厚度依赖性电子结构。

Thickness-dependent electronic structure of intermetallic CeCo2 nanothin films studied by X-ray absorption spectroscopy.

作者信息

Dong Chung-Li, Chen Chi-Liang, Asokan Kandasami, Chang Ching-Lin, Chen Yang-Yuan, Lee Jyh-Fu, Guo Jinghua

机构信息

Institute of Physics, Academia Sinica, Taipei 11529, Taiwan, Republic of China.

出版信息

Langmuir. 2009 Jul 7;25(13):7568-72. doi: 10.1021/la803872w.

DOI:10.1021/la803872w

PMID:19505124

Abstract

We report the electronic structure study of intermetallic CeCo2 nanothin films of various thicknesses by X-ray absorption near-edge structure (XANES) spectroscopy at Ce L3-, Co K-, and L2,3-edges. The Ce L3-edge absorption spectra reveal that the contribution of tetravalent Ce component increases with the film thickness, and all investigated nanothin films exhibit intermediate valence nature. Variation of the spectral intensities observed at the Co K-edge threshold implies modification in the Co 3d states and the enhancement of 3d-4f-5d hybridization. The Co 3d and Ce 4f occupation numbers were estimated from these spectroscopic results. The present study brings out how the surface-to-bulk ratio and the charge transfer between Ce and Co ions affect the electronic structure of nanothin films.

摘要

我们通过在Ce L3-、Co K-和L2,3-边的X射线吸收近边结构（XANES）光谱，报道了不同厚度的金属间化合物CeCo2纳米薄膜的电子结构研究。Ce L3-边吸收光谱表明，四价Ce组分的贡献随薄膜厚度增加，且所有研究的纳米薄膜都表现出中间价态性质。在Co K-边阈值处观察到的光谱强度变化意味着Co 3d态的改变以及3d-4f-5d杂化的增强。从这些光谱结果估算了Co 3d和Ce 4f占据数。本研究揭示了表面与体相之比以及Ce和Co离子之间的电荷转移如何影响纳米薄膜的电子结构。