单层MoSSe力学性质的分子动力学模拟研究  

Molecular dynamics simulation study on mechanical properties of Janus MoSSe monolayer

作　　者：张宇航 李孝宝 詹春晓[1] 王美芹[1] 浦玉学[1] Zhang Yu-Hang;Li Xiao-Bao;Zhan Chun-Xiao;Wang Mei-Qin;Pu Yu-Xue(School of Civil Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学,土木与水利工程学院,合肥230009

出　　处：《物理学报》2023年第4期201-213,共13页Acta Physica Sinica

基　　金：安徽省自然科学基金(批准号:2208085MA17,2208085ME129);中央高校基本科研业务费专项资金(批准号:PA2021KCPY0029)资助的课题。

摘　　要：硫硒化钼(MoSSe)是一种新型二维“双面神”半导体材料,具有丰富的物理、化学、力学与电学性质.本文基于Stillinger-Weber势函数,采用分子动力学模拟方法对不同温度下的完美和含晶界MoSSe单层结构展开详细的力学行为分析.结果表明:完美单层MoSSe结构的力学性能呈现明显的各向异性;在单向拉伸作用下,其杨氏模量、强度极限和极限应变均随温度的升高而降低;当温度低于100 K时,沿锯齿形手性方向受拉伸作用的单层MoSSe结构发生由六环蜂窝相向四方相的相变,新四方相的杨氏模量约为原相结构的1.3倍且强度显著提升;当温度高于100 K时,沿锯齿形手性方向拉伸呈现脆性断裂;含晶界单层MoSSe结构受拉伸作用首先在晶界处产生裂缝,并逐步扩展至整个结构后断裂.锯齿形偏向晶界结构的强度随倾斜角度的增大而降低,扶手椅形偏向晶界结构也呈下降趋势.本研究对基于单层MoSSe的电子器件的强度设计和性能优化具有重要指导意义.This work systematically studies the mechanical responses of a novel semiconducting Janus MoSSe monolayer subjected to uniaxial tensile loadings by molecular dynamics simulations.It is found that the Janus MoSSe monolayer shows clearly anisotropic responses along armchair direction and the zigzag direction.The phase transition behavior is observed when the Janus MoSSe monolayer is under the action of tension along the zigzag direction at temperatures below 100 K,while it does not exist in any other conditions.The Young’s modulus,ultimate strength and ultimate strain decrease with temperature increasing.Particularly,the ductileto-brittle fracture behavior is observed when uniaxial tension is applied along the zigzag direction depending on temperatures.The underline fracture mechanism is analyzed.Moreover,mechanical properties of Janus MoSSe monolayer with various grain boundaries are also carefully explored.It is found that the ultimate strength and ultimate strain depend more sensitively on narrow grains than on those wider ones.The crack is initialized near the grain boundaries and propagates along the direction almost perpendicular to the grain boundaries.The findings of this work may shed light on design and optimization of nanoscale electronic devices based on the Janus MoSSe monolayers.

关 键 词：“双面神”MoSSe 力学性质 晶界 分子动力学 

分 类 号：O469[理学—凝聚态物理]