在高达158 GPa的玻璃状GeO2中没有超过六倍的协调,由X射线吸收光谱学揭示
João Elias F S Rodrigues1, Angelika D Rosa1, Emin Mijit1
1European Synchrotron Radiation Facility, Grenoble 38000, France.
概括
高压X射线吸收光谱揭示了玻璃状的二氧化 (GeO2) 如何压缩. 在极端压力下,它的结构仍然灵活,边缘共享八面体持续到158GPa.
科学领域:
- 材料科学 材料科学 材料科学
- 地质物理学 地质物理学
- 固态化学 固态化学
背景情况:
- 与晶体固体相比,二元氧化物玻璃表现出独特的压缩行为.
- 了解无形材料的高压结构反应对地质物理学和材料科学至关重要.
研究的目的:
- 为了研究高压下高达158 GPa的玻璃状GeO2中 (Ge) 周围的局部结构变化.
- 为了比较玻璃状GeO2的压缩机制与其晶体对应物.
主要方法:
- 高压X射线吸收光谱 (XAS) 使用钻石细胞 (DAC).
- 为了确保结果的可靠性,进行了四次独立的实验运行,带有和没有压力传递介质.
主要成果:
- 压力介质对高达30GPa的GeO键长度没有显著的影响.
- 观察到10-30GPa之间的GeO键长度演变的变异性,类似于晶体多态,表明结构灵活性.
- 从30-158 GPa,边缘共享八面体仍然是玻璃般的GeO2.2中占主导地位的结构图案.
- 压缩主要通过八面体结合角度扭曲到100 GPa发生,过渡到八面体扭曲作为100 GPa以上的主要机制.
- 由于动力约束,玻璃GeO2的紧缩效率略低于晶体类型.
结论:
- 玻璃GeO2在高压下表现出显著的结构灵活性,可以容纳各种原子配置.
- 无形结构的GeO2保持边缘共享八面体作为主要的动机高达158GPa.
- 玻璃状GeO2中的压缩机制与晶体形式略有不同,突出了无形结构对材料对压力的反应的影响.
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