电场作用下边缘修饰石墨烯纳米带的电磁性质

The electronic and magnetic properties of edge-modifiedgraphene nanoribbons in external electric field

采用基于密度泛函理论的第一性原理,研究了非金属原子(B,N)和金属原子(Na,Mn)边缘修饰不同宽度zigzag型石墨烯纳米带(ZGNR)的结构稳定性和电磁性质。并进一步研究了外加不同强度垂直电场对原子边缘修饰ZGNR电磁性质的调控规律,所有原子边缘修饰ZGNR体系均能形成稳定结构。在施加垂直于纳米带平面的电场强度后,随着电场强度的增大,[N-ZG]4体系稳定性最好且基本不变,[Mn-ZG]4体系稳定性增加,而[B-ZG]4和[Na-ZG]4体系稳定性降低;电场促进了边缘修饰原子(B,Na,Mn)的电荷进一步向石墨烯C原子转移,阻碍了电荷从石墨烯C原子向边缘N原子转移;N和Na修饰体系的磁性逐渐减小,而B和Mn修饰体系磁性逐渐增大。研究结果表明,外加不同强度电场可以有效调控原子边缘修饰ZGNR体系的结构稳定性、电子性质和磁性,能够为石墨烯纳米带在纳米电子领域的应用提供理论基础。

The structure stability and electronic and magnetic properties have been calculated for the non-metal(B,N)and metal(Na,Mn)atoms edge-modified zigzag graphene nanoribbons(ZGNR)with different widths by using the first principle method based on density functional theory.Then the modified regulations of electronic structures are investigated for the atoms edge-modified ZGNR systems in electric fields with different intensities.The stable systems can be formed for all the atoms edge-modified ZGNR structures.With the increasing intensity of electric fields perpendicular to the nanoribbon surface,the stability is almost unchanged for the most stable[N-ZG]4 system,and the stability is increases for the[Mn-ZG]4 system but decreases for the[B-ZG]4 and[Na-ZG]4 systems.The electric field promotes the further transfer of charge from atoms(B,Na,Mn)to the C atoms of graphene in[M-ZG]system,and hinders the transfer of charge from C atom to N atom in[N-ZG]system.The magnetisms decrease gradually for the[N-ZG]and[Na-ZG]systems while increase gradually for[B-ZG]and[Mn-ZG]systems.The results show that the structure stability,electronic and magnetic properties can be regulated effectively by the electric fields with different intensities for the atoms edge modified ZGNR systems,which can provide a theoretical basis for the application of graphene nanoribbons in the field of nanoeletronics.