石墨烯位错附近应变场的离散晶格方法研究  

Strain fields around graphene dislocations studied by discrete crystal lattice analyses

作　　者：邵宇飞[1] 杨鑫[1] 高科[2] 李久会[3] 赵星[3] 

机构地区：[1]辽宁工程技术大学应用物理与技术研究所,葫芦岛125105 [2]辽宁工程技术大学安全科学与工程学院,葫芦岛125105 [3]辽宁工业大学理学院,锦州121001

出　　处：《中国科学：物理学、力学、天文学》2017年第6期110-118,共9页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:51404126);辽宁省自然科学基金(编号:201602360);辽宁省教育厅一般科学研究项目(编号:L2014135)资助

摘　　要：位错是石墨烯材料中的一种重要结构缺陷.本文通过基于离散晶格方法的virial局部应变研究了石墨烯位错周围应变场.结果表明两种原子级virial局部应变,即无限小应变和有限应变,与位错弹性理论预测结果吻合较好,从而证明了virial应变分析方法的有效性.然而这两种应变存在微小差异,该差异可以用来显示位错芯域的原子结构.近邻环境对这种应变差异存在影响,根源在于不同的近邻环境对位错芯域局部变形的敏感程度不同:与次近邻环境相比,最近邻环境计算范围较小,计算出的应变差异对局部变形更加敏感.最后,提出近邻位移参数——一种显示石墨烯位错的新方法,该参数可以清晰地显示出石墨烯位错的5|7结构,并能够反映出褶皱引起的结构变化.Dislocation is one kind of the most important structural defects in graphene sheets. In the present work, graphene dislocation is studied through the computational model of a dislocation dipole with two opposite cores. Strain fields around the dislocation cores are calculated at atomic level according to virial strain concept, which is derived from the coordinates of discrete atoms and the symmetry of crystal lattice. Results show that both infinitesimal and finite virial strains are consistent with the predictions from elastic theory very well, thus the accuracy of virial strain analyses is validated. However, there is a slight difference between the two strain fields. The core area of the dislocation dipole can be outlined by the strain differences, which can be influenced by the neighboring atomic structure. Compared with the second nearest neighboring environment, the nearest neighboring environment has a smaller volume, therefore can be influenced by the local deformation state more easily. Finally, a new method to visualize the cores is proposed based on the displacements of graphene atoms. The location and structure of the dislocation dipole predicted by this new method are in agreement with the strain analyses excellently, and the structure changes generated by ripples can also be described.

关 键 词：石墨烯 位错 应变 晶格 

分 类 号：O613.71[理学—无机化学]