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Bond softening in monolayer graphite formed on transition-metal carbide surfaces

colorstone 添加于 2012-4-1 13:36 | 1289 次阅读 | 0 个评论

作者
Aizawa T, Souda R, Otani S, Ishizawa Y, Oshima C
摘要
Full phonon-dispersion curves of the graphitic layer on some transition-metal carbides were measured by using high-resolution electron-energy-loss spectroscopy. The graphitic layer on (111) surfaces of TaC, HfC, and TiC showed anomalous softening within the layer, whereas the graphite layer on TaC(001) is similar to bulk graphite. The measured phonon dispersion has been analyzed with a force-constant model, and it has been revealed that the force constants for vertical angle bending and for bond twisting are much weaker in the former case. This is ascribed to the charge transfer into the overlayer from the substrate, resulting in the weakening of the π bond in graphite. The clear contrast in variations of phonons between the graphitic layer on TaC(111) and that on TaC(001) indicates that the microscopic structure at the interface determines the charge transfer.
详细资料
- 文献种类: Journal Article
- 期刊名称: Physical Review B
- 期刊缩写: Phys. Rev. B
- 期卷页: 1990年第42卷第18期 11469-11478页
- ISBN: 0163-1829
学科领域工程技术 » 材料科学
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