Spectroscopic Evidence for Ultrahigh-Pressure Polymorphism in SiO2 Glass
Spectroscopic Evidence for Ultrahigh-Pressure Polymorphism in SiO2 Glass
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DOI：
10.1103/physrevlett.104.025504
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发表时间：
2010-01-15
影响因子：
8.6
通讯作者：
Bass, Jay D.
中科院分区：
文献类型：
--
作者：
Murakami, Motohiko;Bass, Jay D.
使用新开发的布里渊散射光谱技术，以解决压力引起的结构变化的性质的压力高达207 GPa的SiO2玻璃的声波速度进行测量。声波速度数据表明三个不同的压力制度，其中两个对应于Si-O配位数随压力的变化，其中一个表明六配位Si在40-140 GPa的宽压力区间内的稳定性。在140 GPa的压力对速度的影响的异常增加最有可能对应于结构致密化的发生与配位数从六倍增加到更高的配位状态。
Acoustic wave velocities of SiO2 glass were measured up to pressures of 207 GPa using newly developed Brillouin scattering spectroscopic techniques to address the nature of pressure-induced structural changes. The acoustic wave velocity data suggests three distinct pressure regimes, two of which correspond to changes in the Si-O coordination number with pressure, and one of which indicates the stability of sixfold-coordinated Si over a broad pressure interval from similar to 40-140 GPa. An anomalous increase in the effect of pressure on velocity at 140 GPa most likely corresponds to the onset of structural densification associated with an increase in coordination number from sixfold to a higher coordination state.