期刊
PHYSICAL REVIEW B
卷 74, 期 12, 页码 -出版社
AMERICAN PHYSICAL SOC
DOI: 10.1103/PhysRevB.74.125109
关键词
-
The present controversy over the origin of glasslike thermal conductivity observed in certain crystalline materials is addressed by studies on single-crystal x-ray diffraction, thermal conductivity kappa(T), and specific heat C-p(T) of carrier-tuned Ba8Ga16X30 (X=Ge,Sn) clathrates. These crystals show radically different low-temperature kappa(T) behaviors depending on whether their charge carriers are electrons or holes, displaying the usual crystalline peak in the former case and an anomalous glasslike plateau in the latter. In contrast, C-p(T) above 4 K and the general structural properties are essentially insensitive to carrier tuning. We analyze these combined results within the framework of tunneling scattering, resonant scattering, and Rayleigh scattering models, and conclude that the evolution from crystalline to glasslike kappa(T) is accompanied by an increase both in the effective density of tunneling states and in the resonant scattering level, while neither one of these contributions can solely account for the observed changes in the full temperature range. This suggests that the most relevant factor that determines crystalline or glasslike behavior is the coupling strength between the guest vibrational modes and the frameworks with different charge carriers.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据