The normal-auxeticity mechanical phase transition in graphene
The normal-auxeticity mechanical phase transition in graphene
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DOI：
10.1088/2053-1583/aa61e5
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发表时间：
2017-06-01
期刊：
影响因子：
5.5
通讯作者：
Peng, Qing
中科院分区：
文献类型：
--
作者：
Deng, Binghui;Hou, Jie;Peng, Qing
一般来说，当一个固体物体被拉伸时，它会横向收缩。而异常的则是缺失性的，表现为侧向扩张或负泊松比。虽然石墨烯是一种典型的二维材料，但令人惊讶的是，石墨烯在某些应变下会从正常转变为惰性。在这里，我们通过分子动力学模拟表明，正常的机械相变只发生在沿扶手椅方向或最近邻方向的单轴拉伸中。这种特性在高达2400 K的温度下仍然存在。除了单层石墨烯外，双层和多层石墨烯也具有这种正性转变。这种独特的性质可以将石墨烯的应用扩展到新的领域。
When a solid object is stretched, in general, it shrinks transversely. However, the abnormal ones are auxetic, which exhibit lateral expansion, or negative Poisson ratio. While graphene is a paradigm 2D material, surprisingly, graphene converts from normal to auxetic at certain strains. Here, we show via molecular dynamics simulations that the normal-auxeticity mechanical phase transition only occurs in uniaxial tension along the armchair direction or the nearest neighbor direction. Such a characteristic persists at temperatures up to 2400 K. Besides monolayer, bilayer and multi-layer graphene also possess such a normal-auxeticity transition. This unique property could extend the applications of graphene to new horizons.