Cr掺杂ZnO纳米线电子性质和磁性质

本文采用第一性原理密度泛函理论系统的研究了Cr原子单掺杂和双掺杂两种尺寸ZnO纳米线的电子性质和磁性质.所有掺杂纳米线的形成能都比纯纳米线的形成能低,表明掺杂增强了纳米线的稳定性.研究发现Cr原子趋于替代纳米线表面的Zn原子.所有掺杂纳米线都显示了金属性.纳米线的总磁矩主要来源于Cr原子3d轨道的贡献.由于杂化,相邻的O原子和Zn原子也产生了少量自旋.在超原胞内,Cr和O原子磁矩反平行排列,表明它们之间是反铁磁耦合.表面双掺杂纳米线铁磁态能量比反铁磁态能量低149 meV,表明Cr掺杂ZnO纳米线可能获得室温铁磁性.

Electronic and magnetic properties of Cr-doped ZnO nanowires

The electronic and magnetic properties of two sizes of ZnO nanowires doped with one or two Cr atoms are comparatively studied in terms of the first-principles calculation. The formation energies of doped nanowires are smaller than that of the pristine one, indicating that the doing process enhanced the stability of nanowires. The result shows that Cr atom preferring to the surface position. All doped nanowires show metal character. The magnetic moments are mainly contributed by the Cr-3d orbital. Due to the hybridization interaction, a small magnetic moment is also induced in nearest neighboring O and Zn atoms. The magnetic moments of the C and O atoms have the different direction, indicating antiferromagnetic coupling between them. The large energy difference between the ferromagnetic and antierromagnetic state implies room-temperature ferromagnetism for Cr-doped ZnO nanowires.