Department of Physics and ‡MAX IV Laboratory, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden.
Nano Lett. 2014 Feb 12;14(2):541-6. doi: 10.1021/nl403596b. Epub 2014 Jan 13.
The modified phonon dispersion is of importance for understanding the origin of the reduced heat conductivity in nanowires. We have measured the phonon dispersion for 50 nm diameter InSb (111) nanowires using time-resolved X-ray diffraction. By comparing the sound speed of the bulk (3880 m/s) and that of a classical thin rod (3600 m/s) to our measurement (2880 m/s), we conclude that the origin of the reduced sound speed and thereby to the reduced heat conductivity is that the C44 elastic constant is reduced by 35% compared to the bulk material.
在纳米线中，声子的频散对理解热导率降低的原因具有重要意义。我们使用时间分辨的 X 射线衍射，对 50nm 直径的 InSb(111)纳米线的声子频散进行了测量。通过将块状材料（3880m/s）和经典薄杆（3600m/s）的声速与我们的测量值（2880m/s）进行比较，我们得出结论：导致声速降低以及热导率降低的原因是 C44 弹性常数与块状材料相比降低了 35%。
