1] Department of Physics, National University of Singapore, Singapore 117542, Singapore [2] Graphene Research Center, National University of Singapore, Singapore 117542, Singapore [3] NanoCore, 4 Engineering Drive 3, National University of Singapore, Singapore 117576, Singapore [4].
1] Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany [2].
Nat Commun. 2014 Apr 16;5:3689. doi: 10.1038/ncomms4689.
Graphene exhibits extraordinary electronic and mechanical properties, and extremely high thermal conductivity. Being a very stable atomically thick membrane that can be suspended between two leads, graphene provides a perfect test platform for studying thermal conductivity in two-dimensional systems, which is of primary importance for phonon transport in low-dimensional materials. Here we report experimental measurements and non-equilibrium molecular dynamics simulations of thermal conduction in suspended single-layer graphene as a function of both temperature and sample length. Interestingly and in contrast to bulk materials, at 300 K, thermal conductivity keeps increasing and remains logarithmically divergent with sample length even for sample lengths much larger than the average phonon mean free path. This result is a consequence of the two-dimensional nature of phonons in graphene, and provides fundamental understanding of thermal transport in two-dimensional materials.
石墨烯具有非凡的电子和机械性能，以及极高的热导率。石墨烯是一种非常稳定的原子级薄膜，可以悬浮在两个电极之间，为研究二维系统中的热导率提供了一个完美的测试平台，这对于低维材料中的声子输运至关重要。在这里，我们报告了悬浮单层石墨烯中热导与温度和样品长度关系的实验测量和非平衡分子动力学模拟。有趣的是，与块体材料相反，在 300 K 时，热导率随着样品长度的增加而不断增加，并且即使对于比平均声子平均自由程大得多的样品长度，仍然呈对数发散。这一结果是石墨烯中声子的二维性质的结果，并为二维材料的热输运提供了基本的理解。
