Temperature dependence of atomic vibrations in mono-layer graphene
Temperature dependence of atomic vibrations in mono-layer graphene
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DOI：
10.1063/1.4928324
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发表时间：
2015-08-21
影响因子：
3.2
通讯作者：
Kirkland, Angus I.
中科院分区：
文献类型：
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作者：
Allen, Christopher S.;Liberti, Emanuela;Kirkland, Angus I.
我们测量了单层石墨烯在100 K至1300 K的温度范围内的面内和面外晶格振动的均方振幅。晶格振动的振幅由从在已知温度范围内记录的选定区域电子衍射图案提取的数据计算，每个衍射图案测量超过80个衍射峰。使用分析德拜模型，我们还确定了单层石墨烯晶体可以支持的最大声子波长和量子力学零点振动的幅度。对于面内声子，量子力学零点贡献在室温下占主导地位的测量原子位移，而对于面外模式，必须考虑热填充声子。我们发现一个值的最大声子波长采样是几个数量级小于物理微晶尺寸。(C)2015 AIP Publishing LLC.
We have measured the mean square amplitude of both in-and out-of-plane lattice vibrations for mono-layer graphene at temperatures ranging from similar to 100 K to 1300 K. The amplitude of lattice vibrations was calculated from data extracted from selected area electron diffraction patterns recorded across a known temperature range with over 80 diffraction peaks measured per diffraction pattern. Using an analytical Debye model, we have also determined values for the maximum phonon wavelength that can be supported by a mono-layer graphene crystal and the magnitude of quantum mechanical zero point vibrations. For in-plane phonons, the quantum mechanical zero point contribution dominates the measured atomic displacement at room temperature, whereas for out-of-plane modes, thermally populated phonons must be considered. We find a value for the maximum phonon wavelength sampled that is several orders of magnitudes smaller than the physical crystallite size. (C) 2015 AIP Publishing LLC.