发表机构
School of Physics, State Key Laboratory of Opto-Electronic Information Acquisition and Protection Technology, Anhui University（安徽大学物理学院光电信息获取与保护技术国家重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过2D和3D模型玻璃揭示纵向与横向Ioffe-Regel频率之比受玻璃稳定性强烈控制，稳定玻璃中纵向声衰减不可忽略，挑战了传统假设。
AI 中文摘要
玻璃中热导率的温度依赖性在特征上与晶体中的不同，并且主要受声波如何被阻尼的控制。Ioffe-Regel（IR）频率设定了明确声波的高频极限。尽管横向IR频率已被确定与玻色峰频率一致，并报道远低于纵向IR频率，但纵向与横向IR频率之间的定量关系仍然未知。在此，我们在稳定性差异巨大的二维（2D）和三维（3D）模型玻璃中研究了这一关系。我们观察到，在3D玻璃中，纵向与横向IR频率之比近似等于低频横向与纵向声衰减系数之比，而这一对应关系在2D玻璃中未观察到。此外，我们发现玻璃稳定性在2D和3D玻璃中都强烈控制着纵向与横向IR频率之比：该比值随玻璃稳定性的增加而显著降低，并在所研究的最稳定玻璃中趋近于1。因此，在足够稳定的玻璃中，纵向声衰减应与横向衰减相当，因此不能被视为可忽略，这对尤其是在理论研究中采用的常见假设提出了挑战。我们的工作再次证明了玻璃稳定性是研究玻璃性质的关键参数，并提醒不要简单地将从退火不良玻璃中观察到的结果外推到稳定玻璃。
英文摘要
The temperature dependence of thermal conductivity in glasses differs characteristically from that in crystals, and is largely controlled by how sound waves are damped. The Ioffe-Regel (IR) frequency sets the high-frequency limit of well-defined sound waves. Although the transverse IR frequency has been established to coincide with the boson peak frequency and reported to be far below the longitudinal IR frequency, the quantitative relation between longitudinal and transverse IR frequencies has remained unknown. Here we examine this relation in two- (2D) and three-dimensional (3D) model glasses with vastly different stability. We observe that, in 3D glasses, the longitudinal-to-transverse IR frequency ratio is approximately equal to the ratio of the low-frequency transverse to longitudinal sound attenuation coefficient, whereas this correspondence is not observed in 2D glasses. Moreover, we find that the glass stability strongly controls the longitudinal-to-transverse IR frequency ratio in both 2D and 3D glasses: the ratio decreases significantly with increasing glass stability and approaches unity for the most stable glasses under study. Accordingly, in sufficiently stable glasses, the longitudinal sound attenuation should be comparable to the transverse attenuation, and therefore cannot be treated as negligible, challenging common assumptions adopted especially in theoretical studies. Our work is another demonstration of the glass stability as a key parameter for investigating glass properties, and cautions against simply extrapolating observations from poorly annealed glasses to stable glasses.
Comments9 pages, 6 figures
