Thermal diffuse scattering as a probe of large-wave-vector phonons in silicon nanostructures.
Thermal diffuse scattering as a probe of large-wave-vector phonons in silicon nanostructures.
复制标题
热漫散射作为硅纳米结构中大波矢量声子的探针。
DOI：
10.1103/physrevlett.110.205503
复制
发表时间：
2013
影响因子：
8.6
通讯作者：
P. Evans
中科院分区：
文献类型：
--
作者：
G. Gopalakrishnan;M. Holt;K. McElhinny;J. W. Spalenka;D. Czaplewski;T. Schülli;P. Evans
大波矢声子在决定纳米材料的热学和电学性质方面具有重要作用。然而，这种结构的体积小，对声子色散的实验研究提出了重大挑战。我们表明，同步辐射X射线热漫散射可以适用于探测声子与波矢量跨越整个布里渊区的纳米硅膜。来自厚度为315至6 nm且样品体积小至5 μm（3）的平坦Si纳米膜的热漫散射信号具有预期的对膜厚度的线性依赖性，并且在大波矢量处也表现出过量强度，这与膜的低位大波矢量模式所预期的散射特征一致。
Large-wave-vector phonons have an important role in determining the thermal and electronic properties of nanoscale materials. The small volumes of such structures, however, have posed significant challenges to experimental studies of the phonon dispersion. We show that synchrotron x-ray thermal diffuse scattering can be adapted to probe phonons with wave vectors spanning the entire Brillouin zone of nanoscale silicon membranes. The thermal diffuse scattering signal from flat Si nanomembranes with thicknesses from 315 to 6 nm, and a sample volume as small as 5 μm(3), has the expected linear dependence on the membrane thickness and also exhibits excess intensity at large wave vectors, consistent with the scattering signature expected from low-lying large-wave-vector modes of the membranes.