Universal elastic-hardening-driven mechanical instability in α-quartz and quartz homeotypes under pressure.
Universal elastic-hardening-driven mechanical instability in α-quartz and quartz homeotypes under pressure.
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压力下α-石英和石英同型体中普遍的弹性硬化驱动的机械不稳定性
DOI：
10.1038/srep10810
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发表时间：
2015-06-23
影响因子：
4.6
通讯作者：
Chen D
中科院分区：
文献类型：
--
作者：
Dong J;Zhu H;Chen D
作为冰和类冰材料（特别是α-石英）中压力诱导非晶化（PIA）的一个基本性质，力学不稳定性的发生可能与违反玻恩弹性准则有关。在PIA之前，α-石英最突出的弹性特征是剪切模量C44的线性软化，这被认为是通过Born判据B3触发转变的原因。然而，通过密度泛函理论，我们惊奇地发现α石英中的C44和C66在压缩下都表现出很强的非线性，并且玻恩判据B3的消失主要是由C14的硬化所主导，而不是由C44的减少所主导。对原型石英同源异型（GeO 2和AlPO 4）的进一步研究反复再现了相同的弹性硬化驱动的机械不稳定性，这表明了这一系列晶体的普遍特征，并挑战了长期存在的观点，即个体弹性模量的负压导数可以被解释为PIA之前内在结构不稳定性的前兆效应。文中还讨论了这种弹性异常与最低声分支弥散软化的关系及可能的变形机制。
As a fundamental property of pressure-induced amorphization (PIA) in ice and ice-like materials (notably α-quartz), the occurrence of mechanical instability can be related to violation of Born criteria for elasticity. The most outstanding elastic feature of α-quartz before PIA has been experimentally reported to be the linear softening of shear modulusC44, which was proposed to trigger the transition through Born criteriaB3. However, by using density-functional theory, we surprisingly found that bothC44andC66in α-quartz exhibit strong nonlinearity under compression and the Born criteriaB3vanishes dominated by stiffening ofC14, instead of by decreasing ofC44. Further studies of archetypal quartz homeotypes (GeO2and AlPO4) repeatedly reproduced the same elastic-hardening-driven mechanical instability, suggesting a universal feature of this family of crystals and challenging the long-standing idea that negative pressure derivatives of individual elastic moduli can be interpreted as the precursor effect to an intrinsic structural instability preceding PIA. The implications of this elastic anomaly in relation to the dispersive softening of the lowest acoustic branch and the possible transformation mechanism were also discussed.
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影响因子：
3.3
作者：
Dong, Juncai;Zhang, Xiaoli;Chen, Dongliang
通讯作者：
Chen, Dongliang
DOI：
10.1088/0022-3719/13/36/014
发表时间：
1980-01-01
期刊：
JOURNAL OF PHYSICS C-SOLID STATE PHYSICS
影响因子：
--
作者：
DORNER, B;GRIMM, H;RZANY, H
通讯作者：
RZANY, H
影响因子：
8.6
作者：
Gregoryanz, E;Hemley, RJ;Gillet, P
通讯作者：
Gillet, P
DOI：
10.1107/s056773947700223x
发表时间：
1977-01-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION A
影响因子：
--
作者：
OKEEFFE, M
通讯作者：
OKEEFFE, M
影响因子：
64.8
作者：
BINGGELI, N;CHELIKOWSKY, JR
通讯作者：
CHELIKOWSKY, JR