Zhang Yanyao, Fu Suyu, Wang Baoyun, Lin Jung-Fu
Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78712, USA.
State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Phys Rev Lett. 2021 Jan 15;126(2):025701. doi: 10.1103/PhysRevLett.126.025701.
Elastic moduli (C_{ij}) of single-crystal stishovite and post-stishovite are determined using Brillouin light scattering, impulsive stimulated light scattering, and x-ray diffraction up to 70 GPa. The C_{12} of stishovite converges with the C_{11} at ∼55 GPa, where the transverse wave V_{S1} propagating along [110] also vanishes. Landau modeling of the C_{ij}, B_{1g} optic mode, and lattice parameters reveals a pseudoproper type ferroelastic post-stishovite transition. The transition would cause peculiar anomalies in V_{S} and Poisson's ratio in silica-bearing subducting slabs in the mid-lower mantle.
利用布里渊光散射、脉冲受激光散射和X射线衍射，在高达70吉帕的压力下测定了单晶斯石英和后斯石英的弹性模量（Cij）。斯石英的C12在约55吉帕时与C11收敛，此时沿[110]方向传播的横波VS1也消失。对Cij、B1g光学模式和晶格参数进行的朗道模型研究揭示了一种赝正规型铁弹后斯石英转变。这种转变会在中下地幔含硅俯冲板块的VS和泊松比中引起奇特的异常现象。
