Chen Xue-Kun, Liu Jun, Du Dan, Chen Ke-Qiu
School of Mathematics and Physics, University of South China, Hengyang 421001, People's Republic of China.
J Phys Condens Matter. 2017 Nov 15;29(45):455702. doi: 10.1088/1361-648X/aa8c3e.
The thermal transport properties of graphyne are investigated via equilibrium molecular dynamics (EMD) simulations and non-equilibrium Green's function (NEGF) method. It is found that the room-temperature thermal conductivity of graphyne is 93% lower than that of graphene with a similar size and decreases steeply with increasing the number of acetylenic linkages, which agrees with the results obtained by NEGF method qualitatively. Lattice dynamics calculations reveal that these phenomena can be attributed to the reduction of both phonon group velocities and phonon lifetimes in graphyne at low-frequency region. However, when the temperature is less than 30 K, the thermal conductance of graphyne exceeds that of graphene. Moreover, the anomalous thermal conductance behavior is not sensitive to the system lateral size. The underlying mechanisms for such phenomena are elaborated by the normal mode analysis.
通过平衡分子动力学（EMD）模拟和非平衡格林函数（NEGF）方法研究了石墨炔的热输运性质。研究发现，与类似尺寸的石墨烯相比，石墨炔在室温下的热导率低93%，并且随着炔键数量的增加而急剧下降，这与NEGF方法得到的结果定性一致。晶格动力学计算表明，这些现象可归因于低频区域石墨炔中声子群速度和声子寿命的降低。然而，当温度低于30K时，石墨炔的热导率超过石墨烯。此外，这种反常的热导率行为对系统横向尺寸不敏感。通过简正模式分析阐述了这些现象的潜在机制。
