多层石墨烯的表面起伏的分子动力学模拟

Ripples of multilayer graphenes:a molecular dynamics study

运用经典分子动力学方法,研究了呈现不同堆积方式的多层石墨烯在不同温度下的表面起伏,并且和单层、双层石墨烯做对比,计算发现:室温下,多层石墨烯中存在着横向特征尺寸约为100 A的起伏,该尺寸会随着温度的升高而增大;同时,起伏的高度也随着温度的升高而增大,这些石墨烯的层内起伏高度关联函数都遵从幂指数标度行为G_h(q)αq^(-α),对于同一种石墨烯,温度越高幂指数越小;而在同一温度下,不同堆积方式的石墨烯的幂指数也不同,所有这些特征都来源于温度以及层间耦合作用引起的非谐效应。

Using the classical molecular dynamics simulations, we have investigated the thermally-excited ripples of the multi-layer graphenes at different temperatures, and compared them with those of the single-and doublelayer graphene. It is found that： 1） the ripples in multilayer graphene are intrinsic with a characteristic size of about 100 ？ at room tempe-rature, increasing with increase of temperature;at the same time, the ripple’s height also increases with the temperature;2） the ripple’s intralayer height-height correlation functions for the multilayer graphene follow a power-law behavior, Gh（q）∝q-α;the scaling exponent decreases as temperature increases. Moreover, the scaling exponents are different for different types of multilayer graphene even at the same temperature. All these phenomena result from the anharmonic effects which are induced by the temperature and the interlayer interactions.