Lubchenko Vassiliy, Wolynes Peter G
Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
Proc Natl Acad Sci U S A. 2003 Feb 18;100(4):1515-8. doi: 10.1073/pnas.252786999. Epub 2003 Feb 10.
We argue that the intrinsic glassy degrees of freedom in amorphous solids giving rise to the thermal conductivity plateau and the "boson peak" in the heat capacity at moderately low temperatures are directly connected to those motions giving rise to the two-level-like excitations seen at still lower temperatures. These degrees of freedom can be thought of as strongly anharmonic transitions between the local minima of the glassy energy landscape that are accompanied by ripplon-like domain wall motions of the glassy mosaic structure predicted to occur at T(g) by the random first-order transition theory. The energy spectrum of the vibrations of the mosaic depends on the glass transition temperature, the Debye frequency, and the molecular length scale. The resulting spectrum reproduces the experimental low-temperature boson peak. The "nonuniversality" of the thermal conductivity plateau depends on k(B)T(g)omega(D) and arises from calculable interactions with the phonons.
我们认为，非晶态固体中产生热导率平台以及在适度低温下比热容中“玻色子峰”的本征玻璃态自由度，与在更低温度下出现的类似两能级激发的运动直接相关。这些自由度可被视为玻璃态能量景观局部极小值之间的强非谐跃迁，伴随着随机一级跃迁理论预测在T(g)时发生的玻璃态镶嵌结构的类涟漪子域壁运动。镶嵌结构振动的能谱取决于玻璃化转变温度、德拜频率和分子长度尺度。由此产生的能谱再现了实验低温玻色子峰。热导率平台的“非普适性”取决于k(B)T(g)omega(D)，并源于与声子的可计算相互作用。
