The movement of heat through amorphous solids on an atomic level remains an outstanding question. Recent studies suggest that the primary thermal carrier in amorphous materials, propagons, essentially behaves like phonons. In this work, we provide experimental evidence that shows the interaction between propagons and phonons by utilizing the phase change chalcogenide germanium telluride. A series of ultra-long time-delay time-domain thermoreflectance measurements are used to analyze the scattering of vibrational thermal carriers at the boundaries of amorphous GeTe thin films relative to scattering across a crystalline-amorphous bilayer. We find that amorphous long wavelength propagons that would otherwise scatter can instead be hosted by a crystalline underlayer and its phonon population. This experimental evidence directly demonstrates propagon–phonon interactions in a clear experimental manner.

中文翻译：

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通过多相碲化锗上的晶体基质松弛主元边界散射

在原子水平上通过非晶固体的热量运动仍然是一个悬而未决的问题。最近的研究表明，非晶材料中的主要热载体，传播体，本质上表现得像声子。在这项工作中，我们提供了实验证据，通过利用相变硫族化物碲化锗来显示传播子和声子之间的相互作用。一系列超长延时时域热反射测量用于分析非晶 GeTe 薄膜边界处振动热载流子相对于晶体-非晶双层散射的散射。我们发现原本会散射的非晶长波长传播体可以由结晶底层及其声子群承载。该实验证据以清晰的实验方式直接证明了传播子-声子相互作用。