Inner displacement and directional bonding in transition metal disilicides

过渡金属二硅化物的内位移和定向键合

• 批准号: 09650716
• 负责人: TANAKA Katsushi
• 金额: $ 2.18万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650716/
• 关键词: Transition metal disilicide; Elastic constants; Structural analysis; Co-valent bonding; Maximum entropy method; Electron density distribution; シリコン原子位置; 方向性結合

For the first step of this project, we have measured single crystal elastic constants of transition metal disilicides with the C11_b, C40 and C54 structures. The elastic constants have been analyzed by the valence force field approach where the inter-atomic interaction is classified into two terms ; bond-stretching and bond-bending. Relative values of the coefficients of these two terms for each transition metal disilicide indicate the directionality of the inter-atomic bonding. The directionality of inter-atomic interaction in the materials with the C11_b structure is the strongest one, and that in the materials with the C40 structure are classified into two groups. The strength of TiSi_2 is located at the middle position between the two groups of the C40 structure.For the next step, we have performed the X-ray analysis to refine the crystallographic parameters of these compounds. The analysis indicates that the position of silicon atoms in the materials are slightly displaced from the position compiled in the data book. The displacement is associated with the anisotropic inter-atomic interactions of Si-Si and Si-TM.This is clearly demonstrated from the electron distribution maps which are constructed from the measured intensities of the diffraction by the maximum entropy method.

在该项目的第一步中，我们测量了具有 C11_b、C40 和 C54 结构的过渡金属二硅化物的单晶弹性常数。弹性常数已通过价态力场方法进行了分析，其中原子间相互作用分为两项；键拉伸和键弯曲。每种过渡金属二硅化物的这两项系数的相对值表明原子间键合的方向性。 C11_b结构材料中原子间相互作用的方向性最强，C40结构材料中原子间相互作用分为两类。 TiSi_2的强度位于两组C40结构之间的中间位置。下一步，我们进行了X射线分析来细化这些化合物的晶体学参数。分析表明，材料中硅原子的位置与数据手册中编制的位置略有偏差。该位移与 Si-Si 和 Si-TM 的各向异性原子间相互作用有关。这可以从通过最大熵法测量的衍射强度构建的电子分布图清楚地证明。

项目成果

K.Tanaka, H.Inui, M.Yamaguchi and M.Koiwa: "Directional atomic bonds in MoSi_2 and other transition-metal disilicides with the C11_

K.Tanaka、H.Inui、M.Yamaguchi 和 M.Koiwa：“MoSi_2 和其他具有 C11_<b> C40 和 C54 结构的过渡金属二硅化物中的定向原子键”Mater.Sci.Eng.Vol.A261。

K.Tanaka, K.Nawata, H.Inui, M.Yamaguchi and M.Koiwa: "Temperature dependence of Single-crystal elastic constants of Mo(Si, Al)_2" Intermetallics. Vol.6. 607-611 (1998)

K.Tanaka、K.Nawata、H.Inui、M.Yamaguchi 和 M.Koiwa：“Mo(Si, Al)_2 单晶弹性常数的温度依赖性”金属间化合物。

K.TANAKA et al: "Single-crystal elastic constants of MoSi_2 with the C11_b structure" Mater.Sci.Eng.A239-240. 188-194 (1997)

K.TANAKA 等人：“具有 C11_b 结构的 MoSi_2 的单晶弹性常数”Mater.Sci.Eng.A239-240。

K.Tanaka et al.: "Temperature dependence of single-crystal elastic constants of Mo (Si, Al)_2" Intermetallics. 6. 607-611 (1998)

K.Tanaka 等人：“Mo (Si, Al)_2 单晶弹性常数的温度依赖性”金属间化合物。

K.Tanaka et al.: "Directional atomic bonds in MoSi_2 and other transition-metall disilicides with the C11_b, C40 and C54 structures." Mater.Sci.Eng.A261. 158-164 (1999)

K.Tanaka 等人：“MoSi_2 和其他过渡金属二硅化物中具有 C11_b、C40 和 C54 结构的定向原子键。”