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采用基于密度泛函理论的广义梯度近似(GGA),对不同尺寸(N=2—11)的单层正三角锯齿型石墨烯量子点(ZN-GNDs)的结构进行优化,得到与实验数据较好符合的晶格常数,进一步计算得到不同尺寸下体系的自旋多重度、磁矩、电子态密度以及自旋电子密度.结果表明:所有体系都呈现金属性,在尺寸较小的体系中量子尺寸效应对电子结构的影响比较明显;与单层石墨烯片一样,sp2杂化作用和非键态电子在量子点中仍起到非常重要的作用;费米能级上有自旋向上的电子分布,体系的自旋多重度和总磁矩随着体系尺寸的增大而增大,分析认为总磁矩主要来自于锯齿形边界上碳原子的2p轨道上非键态电子的贡献.本工作对基于三角锯齿型石墨烯量子点的器件设计具有指导意义.
The structures of monolayer zN-GNDs with different sizes (N = 2-11) were optimized by GGA based on the density functional theory. The experimental data were compared with the experimental data Good coincident lattice constants and further calculated the spin multiplicity, the magnetic moment, the electronic state density and the spin electron density of the system under different sizes.The results show that all the systems are metallic, and in the smaller system quantum The effect of size effect on the electronic structure is obvious. Like monolayer graphene sheets, sp2 hybridization and non-bonding electrons still play a very important role in quantum dots. Electrons with spin-up on the Fermi level Distribution, the spin multiplicity and the total magnetic moment of the system increase with the increase of the size of the system. The analysis shows that the total magnetic moment mainly comes from the contribution of the non-bonding electrons on the 2p orbital of the carbon atom in the jagged boundary. It is instructive to design the device based on triangular zigzag graphene quantum dot.