具有负泊松比效应的2D碳纳米结构设计及其性能的理论计算研究

Design and properties of 2D carbon nanostructure with negative Poisson’s ratio effect:A theoretical computational study

本文利用第一性原理PBE密度泛函理论计算的方法设计了一种由炔基链、吡啶环及少量氢原子组成的具有内凹六边形结构单元的新型理想二维碳纳米结构,并对其平面内负泊松比效应等力学性能和光学性能与电子结构进行了预测.计算表明,该2D材料具有较好的结构稳定性和特殊的力学性能.当将该2D结构在面内(bc面)沿c方向压缩时,其在b方向收缩;当沿c方向拉伸时,其在b方向伸长,即该2D结构同样具有期望的负泊松比效应.材料的泊松比为-3.26;将该2D结构沿b方向拉伸时,c方向将随之伸长;沿b方向压缩时,c方向将随之收缩.沿b方向拉伸或压缩时,泊松比约为-1.951.即该2D材料在面内具有非常显著的负泊松比效应.此外,该2D材料表现出半导体材料的电子结构特征和良好的光反射和折射性能.希望本工作能为具有本征负泊松比效应和优良电子与光学功能的理想二维碳纳米材料的开发提供一种理想的结构设计策略.

In this paper,a novel 2D carbon nanostructure with a re-entrant hexagonal structure unit composed of alkynyl chain,pyridine ring and a small amount of hydrogen atoms is designed by using the first principles PBE density functional theory calculation method.The mechanical properties,optical properties,electronic structure and the in-plane negative Poisson’s ratio effect are predicted.The results show that this 2D material has good structural stability and special mechanical properties.When the 2D structure is compressed along the c direction in-plane(bc plane),it shrinks in the b direction;when stretched along the c direction,it elongates in the b direction,which means that the 2D structure also has the expected negative Poisson's ratio effect.The corresponding Poisson's ratio of the material is-3.26;when the 2D structure is stretched along the b direction,the size in c direction will be elongated;when the 2D structure is compressed along the b direction,that in c direction will shrink.And the corresponding Poisson's ratio is about-1.951 when it is stretched or compressed along b direction.That is to say,the designed 2D material has a very significant negative Poisson's ratio effect in-plane.In addition,this 2D structure shows a semiconductor electronic structure characteristics and good light reflection and refraction properties.It is hoped that this work would provide an ideal structural design strategy for the development of ideal 2D carbon nanomaterials with intrinsic negative Poisson's ratio effect and excellent electronic and optical functions.