面心立方单晶镍纳米线稳定性及磁性的第一性原理计算

Stability and magnetism of fcc single-crystal nickel nanowires by first principles calculations

本文采用第一性原理方法,研究了轴向为低指数晶向的面心立方(fcc)单晶镍纳米线的稳定性和磁性.计算表明,[110]是fcc镍纳米线最容易出现的取向,[111]取向次之,而[001]取向则很难出现,这一结果与实验事实符合.镍纳米线按照原子位置和磁性强弱的不同,可以分成简单的芯-壳结构,在纳米线芯部,原子的磁矩大小与块体基本一致.在纳米线表面,镍原子的磁矩比芯部原子有所增加.表面原子磁矩与轴向的取向相关,[110]为轴向的纳米线表面原子磁矩最低,而[001]为轴向的纳米线表面原子磁矩最高.

The stability and magnetism in fcc single-crystal nickel nanowires with low-index axial direction are studied by first principles methods in this work. For fcc nickel nanowires,it is found that [110]is the most stable direction,while [111]is less stable and [001]the least stable. Nickel nanowires can be described by a simple core-shell model. The core atoms of nanowires have almost the same magnetic moment as in bulk metal. Surface atoms of nickel nanowires have larger atomic magnetic moments in varying degrees related to axial direction. In our calculated nanowires with low-index axial directions,surface atoms in [110]nanowires have lowest magnetic moments while those in [100]nanowires have the largest.