摘要
利用经典分子动力学方法,通过对单层MoS_2力学行为进行单轴拉伸仿真模拟,研究空位缺陷对结构力学性能的影响。结合第一性原理计算,初步探索了单层MoS_2的宏观力学行为与其微观电子结构变化的关联影响。模拟结果表明:空位缺陷使单层MoS_2的力学性能严重劣化,且其影响程度随空位缺陷类型的不同而存在差异,与V_S相比,V_(S2)对上述力学性能的影响更为显著,浓度为0.4%的V_S及V_(S2)缺陷可使MoS_2断裂极限下降10%和23%,且降幅随缺陷浓度的增加而增加。此外,单轴拉伸与V_S、V_(S2)等空位缺陷的存在,均可显著降低单层MoS_2的禁带宽度,这可能与拉伸和空位缺陷均能引起Mo-d和S-p轨道杂化强度与Mo-S键键强的减弱有关。
Effect of vacancy defects on mechanical properties of monolayer MoS2 was investigated by simulating uniaxial tensile behavior with classical molecular dynamics method.Correlation between macroscopic mechanical behavior and electronic structure was preliminarily explored by using first-principle calculations.It is indicated that vacancy defects can seriously degrade mechanical properties,and reduce band-gap width.The degree of influence varies with the types of vacancy defects.Deterioration effect induced by VS2(two sulfur missing vacancy)is more serious than that induced by VS(one sulfur missing vacancy).It is also found that the fracture limit of the monolayer MoS2 decreases with the defect concentration.At the concentration of 0.4%it decreases by around 10%and 23%for VS and VS2 defects,respectively.In addition,both the uniaxial tensile and vacancy defects can all decrease of the band-gap of monolayer MoS2,as is probably ascribed to the fact that both the uniaxial tensile behavior and the existence of the vacancy defects could lower intensity of the hybridization between Mo-d and S-p states and the strength of Mo-S bonds.
作者
潘妍宏
张铭
林申晔
崔艳雷
张威
PAN Yanhong;ZHANG Ming;LIN Shenye;CUI Yanlei;ZHANG Wei(College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China)
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2019年第2期238-243,共6页
Journal of Materials Science and Engineering
基金
国家自然科学基金资助项目(11774017)
北京市创新团队资助项目(IDHT20170502)
关键词
MOS2
空位缺陷
力学性能
分子动力学
MoS2
vacancy defects
mechanical properties
molecular dynamics
