Department of Physics, Jackson State University , Jackson, Mississippi 39217, United States.
Nano Lett. 2014 Mar 12;14(3):1590-5. doi: 10.1021/nl404837e. Epub 2014 Feb 28.
It is demonstrated that the frequency of the extensional vibrational mode of a nanorod made of an elastically anisotropic crystalline material deviates widely from the predictions of the theories based on the analysis of the long-wavelength limit. The dispersion relation for the fundamental extensional mode of a gold rod grown in the [100] direction is calculated and found to be in excellent agreement with experimental data obtained from the transient optical absorption measurements on gold nanorods. This explains an anomaly in the elastic properties of nanorods which was previously attributed to a 26% decrease in Young's modulus for nanorods compared to its bulk value. The developed approach allows one to investigate the role of the crystal structure anisotropy for acoustic phonons in nanorods and nanowires made of any metal or semiconductor material having cubic crystal structure.
研究表明，各向异性弹性单晶纳米棒的伸缩振动模式的频率与基于长波极限分析的理论预测有很大的偏差。计算了沿[100]方向生长的金纳米棒的基本伸缩模式的频散关系，并与通过瞬态光吸收测量金纳米棒获得的实验数据非常吻合。这解释了以前归因于纳米棒的杨氏模量比其体值降低 26%的纳米棒弹性性质的异常。所开发的方法可以研究各向异性晶体结构对纳米棒和纳米线中声学声子的作用，这些纳米棒和纳米线由具有立方晶体结构的任何金属或半导体材料制成。
