Critical curvature localization in graphene. II. Non-local flexoelectricity-dielectricity coupling
Critical curvature localization in graphene. II. Non-local flexoelectricity-dielectricity coupling
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DOI：
10.1098/rspa.2018.0671
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发表时间：
2019-01-01
影响因子：
3.5
通讯作者：
Kim, Kyung-Suk
中科院分区：
文献类型：
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作者：
Kothari, Mrityunjay;Cha, Moon-Hyun;Kim, Kyung-Suk
作为第一部分的续集(Kothari等人2018年上半年R.Soc.A474,20180054)，我们给出了多层石墨烯的弯曲电本构律的一般热力学框架，并用这些定律解释了褶皱在高取向热解石墨表面特殊的分子吸附特性中的作用。热力学上一致的本构关系导致了具有挠曲-介电耦合的机电变形引起的极化的非局部相互作用模型。非局域模型预测的曲率和极化局域化沿皱纹山谷和山脊与密度泛函理论(DFT)计算的结果非常接近。我们的分析表明，非本地模型可以简化为简化的UC本地模型或e本地模型(Kothari等人)。2018年上半年R.Soc.A474,20180054)仅当曲率分布均匀或高度局部化时。对于非局域模型，我们对MLG的层数相关介电系数和本征挠曲电系数进行了标定和公式推导。此外，我们还得到了UC局域和e局域模型的层数相关的挠曲电系数。我们的密度泛函分析表明，中性分子在褶皱脊处的极化诱导吸附依赖于分子的相对分子质量。此外，我们对石墨烯褶皱中极化局域化的详细研究使我们能够理解C-60巴克球在HOPG表面线性阵列中的自组织吸附。
As a sequel of part I (Kothari et al. 2018 Proc. R. Soc. A 474, 20180054), we present a general thermodynamic framework of flexoelectric constitutive laws for multi-layered graphene (MLG), and apply these laws to explain the role of crinkles in peculiar molecular adsorption characteristics of highly oriented pyrolytic graphite (HOPG) surfaces. The thermodynamically consistent constitutive laws lead to a non-local interaction model of polarization induced by electromechanical deformation with flexoelectricity-dielectricity coupling. The non-local model predicts curvature and polarization localization along crinkle valleys and ridges very close to those calculated by density functional theory (DFT). Our analysis reveals that the non-local model can be reduced to a simplified uc-local or e-local model (Kothari et al. 2018 Proc. R. Soc. A 474, 20180054) only when the curvature distribution is uniform or highly localized. For the non-local model, we calibrated and formulated the layer-number-dependent dielectric and intrinsic flexoelectric coefficients of MLGs. In addition, we also obtained layer-number dependent flexoelectric coefficients for uc-local and e-local models. Our DFT analysis shows that polarization-induced adsorption of neutral molecules at crinkle ridges depends on the molecular weight of the molecule. Furthermore, our detailed study of polarization localization in graphene crinkles enables us to understand previously unexplained self-organized adsorption of C-60 buckyballs in a linear array on an HOPG surface.