Myint Peco, Ludwig Karl F, Wiegart Lutz, Zhang Yugang, Fluerasu Andrei, Zhang Xiaozhi, Headrick Randall L
Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, USA.
Department of Physics and Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, USA.
Phys Rev Lett. 2021 Jan 8;126(1):016101. doi: 10.1103/PhysRevLett.126.016101.
Investigating the relationship between structure and dynamical processes is a central goal in condensed matter physics. Perhaps the most noted relationship between the two is the phenomenon of de Gennes narrowing, in which relaxation times in liquids are proportional to the scattering structure factor. Here, a similar relationship is discovered during the self-organized ion-beam nanopatterning of silicon using coherent x-ray scattering. However, in contrast to the exponential relaxation of fluctuations in classic de Gennes narrowing, the dynamic surface exhibits a wide range of behaviors as a function of the length scale, with a compressed exponential relaxation at lengths corresponding to the dominant structural motif-self-organized nanoscale ripples. These behaviors are reproduced in simulations of a nonlinear model describing the surface evolution. We suggest that the compressed exponential behavior observed here is due to the morphological persistence of the self-organized surface ripple patterns which form and evolve during ion-beam nanopatterning.
研究结构与动力学过程之间的关系是凝聚态物理的核心目标。两者之间最著名的关系或许是德热纳窄化现象，即液体中的弛豫时间与散射结构因子成正比。在此，利用相干X射线散射对硅进行自组织离子束纳米图案化过程中发现了类似的关系。然而，与经典德热纳窄化中涨落的指数弛豫不同，动态表面表现出随长度尺度变化的多种行为，在对应于主导结构 motif——自组织纳米级波纹的长度处呈现压缩指数弛豫。这些行为在描述表面演化的非线性模型模拟中得以重现。我们认为，此处观察到的压缩指数行为是由于在离子束纳米图案化过程中形成并演化的自组织表面波纹图案的形态持续性所致。
