玻璃稳定性对气相沉积玻璃低频振动的影响
Effect of glass stability on the low frequency vibrations of vapor deposited glasses
AI总结：
研究通过实验揭示了玻璃稳定性对低频振动模式的影响，发现低频振动模式不受稳定性影响，而高频振动模式则高度敏感。
摘要：
通过物理气相沉积有机分子制备的超稳定玻璃具有非常低的双态态密度，这些玻璃缺陷决定了其独特的低温热性质。数值模拟表明，在与双态态相关的软区域中会出现准局域化谐振振动模式。然而，低频振动模式与玻璃局部结构不稳定性之间的联系仍不清楚。本文利用 recently 开发的核共振分析非弹性X射线散射光谱仪，对超稳定和传统玻璃的非晶薄膜的振动态密度进行了探测，最低频率降至约70GHz。我们证明，尽管双态态密度减少了近一个数量级，玻璃稳定性并不影响最低频率的谐振振动模式。同时，围绕玻色峰最大值的高频振动模式对玻璃稳定性极为敏感。尽管我们无法排除玻璃中可能存在准局域化模式的可能性，但我们证明其存在并非严格必要以描述测得的低频振动密度。本文提出的实验发展为解决玻璃低频振动的长期争论铺平了道路。
英文摘要：
Ultra-stable glasses prepared from the physical vapor deposition of organic molecules present a very low density of two-level states, the kind of glass defects that determine their peculiar low temperature thermal properties. Numerical simulations suggest that quasi-localized harmonic vibrational modes emerge in the soft regions associated with two-level states. However, the connection between the low frequency vibrational modes and the local structural instabilities of glasses remains unexplained. Here we exploit a recently developed spectrograph for nuclear resonant analysis of inelastic X-ray scattering to probe the density of vibrational states of amorphous thin films of ultra-stable and conventional glasses down to an exceptionally low frequency of $\sim 70$ GHz. We show that the glass stability does not affect the harmonic vibrational modes at the lowest frequencies, despite a reduction of almost an order of magnitude in the density of two-level states. At the same time, the vibrational modes at higher frequencies, around the boson peak maximum, are extremely sensitive to the glass stability. Although we cannot exclude the possible existence of quasi-localized modes in glasses, we show that their presence is not strictly necessary to describe the measured density of low frequency vibrations. The experimental developments here presented pave the way to the solution to the long-standing debate on the low frequency vibrations in glasses.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
