Pressure-induced structural modulations in coesite
Pressure-induced structural modulations in coesite
复制标题
柯石英中压力诱导的结构调制
DOI：
10.1103/physrevb.98.104106
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发表时间：
2018-09
影响因子：
3.7
通讯作者：
Redfern Simon A. T.
中科院分区：
文献类型：
--
作者：
Wu Ye;Liu Hanyu;Huang Haijun;Fei Yingwei;Feng Xiaolei;Redfern Simon A. T.
二氧化硅相，SiO2，作为凝聚态物理学、材料科学和（鉴于其在地壳中的丰度）地球科学领域中的重要相，已经引起了极大的关注。在这里，我们从实验和理论上证明柯石英在高压下经历结构调制。柯石英在22-25 GPa转变为畸变调制结构，柯石英-Ⅱ，调制波矢q= 0.5b_2。Coesite-II在36-40 GPa下沿着y轴显示出进一步的相称调制，并且长程有序的晶体结构在超过30 - 40 GPa时崩溃并开始非晶化。第一性原理计算阐明了柯石英的调制相变的本质，并阐明了柯石英的调制结构所造成的调制沿着y轴方向。的结构调制被证明是由于声子不稳定性，压力诱导的非晶化之前。减压后回收的样品形成了结晶柯石英结构的边缘，但其内部仍然是低结晶或部分无定形的。研究结果不仅阐明了柯石英的压力诱导可逆相变和非晶化起源于沿着y轴方向的结构调制，而且揭示了SiO2在高压下的致密化机理.
Silica phases, SiO2, have attracted significant attention as important phases in the fields of condensed-matter physics, materials science, and (in view of their abundance in the Earth's crust) geoscience. Here, we experimentally and theoretically demonstrate that coesite undergoes structural modulations under high pressure. Coesite transforms to a distorted modulated structure, coesite-II, at 22–25 GPa with modulation wave vector q=0.5b∗. Coesite-II displays further commensurate modulation along the y axis at 36–40 GPa and the long-range ordered crystalline structure collapses beyond ∼40GPa and starts amorphizing. First-principles calculations illuminate the nature of the modulated phase transitions of coesite and elucidate the modulated structures of coesite caused by modulations along the y-axis direction. The structural modulations are demonstrated to result from phonon instability, preceding pressured-induced amorphization. The recovered sample after decompression develops a rim of crystalline coesite structure, but its interior remains low crystalline or partially amorphous. Our results not only clarify that the pressure-induced reversible phase transitions and amorphization in coesite originate from structural modulations along the y-axis direction, but also shed light on the densification mechanism of silica under high pressure.
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影响因子：
3.7
作者：
D. Dean;R. Wentzcovitch;N. Keskar;J. Chelikowsky;N. Binggeli
通讯作者：
D. Dean;R. Wentzcovitch;N. Keskar;J. Chelikowsky;N. Binggeli
影响因子：
8.6
作者：
Yunfeng Liang;C. R. Miranda;S. Scandolo
通讯作者：
Yunfeng Liang;C. R. Miranda;S. Scandolo
影响因子：
--
作者：
P. Heaney
通讯作者：
P. Heaney
影响因子：
3.7
作者：
Kresse, G;Furthmuller, J
通讯作者：
Furthmuller, J
影响因子：
56.9
作者：
KINGMA, KJ;MEADE, C;VEBLEN, DR
通讯作者：
VEBLEN, DR