多壳层铜纳米线结构和电子特性的第一性原理研究
First-principles study of the structural and electronic properties of multi-shell copper nanowires

基于密度泛函理论框架下的第一性原理计算，系统地研究了多壳层Cu纳米线的稳定结构和电子特性。得到不同线径多壳层Cu纳米线的平衡态晶格常数相差不大，都表现出金属特性，且其单原子平均结合能和量子电导随着纳米线直径的增加而增加。纳米线中内壳层Cu原子表现出体相结构Cu原子相似的电子特性，而表面壳层由于配位数的减少，其3d态能量范围变窄且整体向费米能级发生移动。电荷密度分析表明，相对于体相Cu晶体中原子间的相互作用，纳米线表面壳层Cu原子与其最近邻原子间的相互作用明显增强。
By using first-principles calculations based on density-functional theory, the stability, structural and electronic and magnetic properties of multi-shell copper (Cu) nanowires have been systematically investigated. It is found that the equilibrium lattice constants are nearly same for all studied multi-shell Cu nanowires with different diameters. All the nanowires are metallic and the binding energy per atom and the quantum conductance show significant increase as the size of the nanowire increases. The results show that the electronic properties are bulklike for atoms on the inner shell of multi-shell Cu nanowires. However, lower coordinated atoms on the surface shell of the multi-shell nanowires have their electronic properties characterized by narrower 3d state shifted toward the Fermi energy. Finally, the charge density reveals that the interactions between the atoms of surface shell and their first nearest neighbor atoms are enhanced in multi-shell Cu nanowires as compared with those in bulk Cu.