论文标题
双层石墨烯中的扭曲和拉伸Moiré超晶格的拓扑衍生的位错理论
A topologically-derived dislocation theory for twist and stretch moiré superlattices in bilayer graphene
论文作者
论文摘要
我们在2D材料双层中开发了对扭曲和拉伸Moire超级晶格的连续脱位描述。连续公式基于与Moire结构相关的周期性位错网络引入的拓扑约束。该方法基于分析解决拓扑约束并最小化总能量的结构失真和位移场的求解。总能量是由每个单个扭曲层的应变能描述的，以及由堆叠不正确引起的peierls-nabarro像界面贡献一样。由于两种贡献之间的竞争，脱位核心在形式主义中自然出现。此处介绍的方法捕获了具有任意方向和特征的扭曲和拉伸Moire超级晶格的结构和能量学，而没有假设先验分析解决方案，而没有可调参数，同时自然考虑了位错位置图像图像相互作用。与使用经典电势的原子模拟相比，最大结构偏差为6％，而最大线能偏差为0.019 eV/Angstrom。显示了我们模型的几种应用，包括用扭角预测结构的变化，并描述脱位线张力和连接能。
We develop a continuum dislocation description of twist and stretch moire superlattices in 2D material bilayers. The continuum formulation is based on the topological constraints introduced by the periodic dislocation network associated with the moire structure. The approach is based on solving analytically for the structural distortion and displacement fields that satisfy the topological constraints, and which minimize the total energy. The total energy is described by both the strain energy of each individual distorted layer, and a Peierls-Nabarro like interfacial contribution arising from stacking disregistry. The dislocation core emerges naturally within the formalism as a result of the competition between the two contributions. The approach presented here captures the structure and energetics of twist and stretch moire superlattices of dislocations with arbitrary direction and character, without assuming an analytical solution a priori, with no adjustable parameters, while accounting naturally for dislocation-dislocation image interactions. In comparisons to atomistic simulations using classical potentials, the maximum structure deviation is 6%, while the maximum line energy deviation is 0.019 eV/Angstrom. Several applications of our model are shown, including predicting the variation of structure with twist angle, and describing dislocation line tension and junction energies.
