论文标题
碳纳米结构中第二种声音的建模
Modeling of second sound in carbon nanostructures
论文作者
论文摘要
在发现高温烯电导率之后，对低维材料的热传输的研究最近引起了很多关注。在这里，我们在低维碳结构中研究了对通过观察第二种声音揭示的流体动力学状态感兴趣的低维碳结构的传输。我们证明，此类二维系统的正确数值建模需要对温度波的半经典分子动力学模拟，这些动力波考虑了热元声子的量子统计数据。我们揭示第二个声音可以归因于碳结构弯曲光学振荡的最大组速度，并且流体动力效应消失在$ t> 200 $ K上，被热波的扩散动力学所取代。我们的数值结果表明，这种低维结构中第二声音的速度约为6 km/s，并且在碳纳米管而不是碳纳米管中，水动力效应表现出更强的表现。
The study of thermal transport in low-dimensional materials has attracted a lot of attention recently after discovery of high thermal conductivity of graphene. Here we study numerically phonon transport in low-dimensional carbon structures being interested in the hydrodynamic regime revealed through the observation of second sound. We demonstrate that correct numerical modeling of such two-dimensional systems requires semi-classical molecular dynamics simulations of temperature waves that take into account quantum statistics of thermalized phonons. We reveal that second sound can be attributed to the maximum group velocity of bending optical oscillations of carbon structures, and the hydrodynamic effects disappear for $T>200$K, being replaced by diffusive dynamics of thermal waves. Our numerical results suggest that the velocity of second sound in such low-dimensional structures is about 6 km/s, and the hydrodynamic effects are manifested stronger in carbon nanotubes rather than in carbon nanoribbons.
