Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
Science. 2012 Jul 13;337(6091):209-12. doi: 10.1126/science.1217529.
The movement of dislocations in a crystal is the key mechanism for plastic deformation in all materials. Studies of dislocations have focused on three-dimensional materials, and there is little experimental evidence regarding the dynamics of dislocations and their impact at the atomic level on the lattice structure of graphene. We studied the dynamics of dislocation pairs in graphene, recorded with single-atom sensitivity. We examined stepwise dislocation movement along the zig-zag lattice direction mediated either by a single bond rotation or through the loss of two carbon atoms. The strain fields were determined, showing how dislocations deform graphene by elongation and compression of C-C bonds, shear, and lattice rotations.
位错在晶体中的运动是所有材料发生塑性变形的关键机制。位错的研究一直集中在三维材料上，而关于位错的动力学及其对石墨烯晶格结构的原子级影响的实验证据很少。我们使用单原子灵敏度研究了在石墨烯中位错对的动力学，并用实验记录了下来。我们检查了沿着锯齿形晶格方向的位错的逐步运动，这些运动是通过单个键的旋转或通过失去两个碳原子来介导的。我们确定了应变场，展示了位错如何通过 C-C 键的拉伸和压缩、剪切和晶格旋转来使石墨烯变形。
