Antao Sytle M, Benmore Chris J, Li Baosheng, Wang Liping, Bychkov Evgeny, Parise John B
Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
Phys Rev Lett. 2008 Mar 21;100(11):115501. doi: 10.1103/PhysRevLett.100.115501. Epub 2008 Mar 18.
Acoustic measurements using synchrotron radiation have been performed on glassy GeSe2 up to pressures of 9.6 GPa. A minimum observed in the shear-wave velocity, associated anomalous behavior in Poisson's ratio, and discontinuities in elastic moduli at 4 GPa are indicative of a gradual structural transition in the glass. This is attributed to a network rigidity minimum originating from a competition between two densification mechanisms. At pressures up to 3 GPa, a conversion from edge- to corner-sharing tetrahedra results in a more flexible network. This is contrasted by a gradual increase in coordination number with pressure, which leads to an overall stiffening of the glass.
利用同步辐射进行了声学测量，测量范围覆盖了高达9.6吉帕压力下的玻璃态GeSe₂。在4吉帕时观测到的剪切波速度最小值、泊松比相关的异常行为以及弹性模量的不连续性，表明玻璃中存在逐渐的结构转变。这归因于两种致密化机制之间竞争导致的网络刚性最小值。在高达3吉帕的压力下，从边共享四面体到角共享四面体的转变导致网络更加灵活。与之形成对比的是，配位数随压力逐渐增加，这导致玻璃整体变硬。
