Department of Materials Science and Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States.
Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan.
ACS Appl Mater Interfaces. 2017 Sep 6;9(35):29438-29444. doi: 10.1021/acsami.7b08945. Epub 2017 Aug 24.
Grain boundaries (GBs) are unavoidable crystal defects in polycrystalline materials and significantly influence their properties. However, the structure and chemistry of GBs in 2D transition metal dichalcogenide alloys have not been well established. Here we report significant chemical selectivity of transition metal atoms at GB dislocation cores in MoWS monolayers. Different from classical elastic field-driven dislocation segregation in bulk crystals, the chemical selectivity in the 2D crystals originates prominently from variation of atomic coordination numbers at dislocation cores. This observation provides atomic insights into the topological effect on the chemistry of crystal defects in 2D materials.
晶界（GBs）是多晶材料中不可避免的晶体缺陷，对其性能有重要影响。然而，二维过渡金属二卤化物合金中的 GB 结构和化学性质尚未得到很好的确定。在这里，我们报道了 MoWS 单层中 GB 位错核中过渡金属原子的显著化学选择性。与体晶体中经典的弹性场驱动位错偏析不同，二维晶体中的化学选择性主要源于位错核中原子配位数的变化。这一观察结果为拓扑效应对二维材料中晶体缺陷化学的影响提供了原子层面的理解。
