采用自旋极化密度泛函理论系统研究了Cr掺杂ZnO纳米线的电学、磁学以及光学属性.计算结果显示,Cr原子沿[0001]方向替代ZnO纳米线中的Zn原子时体系一般呈现铁磁耦合,沿[10-10]和[01-10]方向替代Zn原子时体系呈现反铁磁耦合,且磁性耦合状态在费米能级附近出现了明显的自旋劈裂现象,发生了强烈的Cr3d和O2p杂化效应.自旋态密度计算结果显示,磁矩主要来源于Cr原子未成对3d态电子的贡献,磁矩的大小与Cr原子的电子排布有关.光学性质计算结果显示,Cr掺杂ZnO纳米线在远紫外和近紫外都具有明显的吸收峰,吸收峰发生了明显的红移.这些结果都表明Cr掺杂ZnO纳米线也许是一种很有前途的稀磁半导体材料.%According to the spin-polarized density functional theory,we study the electronic structures,the magnetic and the optical properties of Cr-doped ZnO nanowires.The calculated results show ferromagnetic coupling for Cr atoms substitution for Zn atoms in ZnO nanowires along the 0001 direction,and the antiferromagnetic coupling with Cr-doped in ZnO nanowires along the 101-0 and 011-0 directions.The results reveal that the magnetic coupling state near the Fermi level gives rise to such a spin splitting phenomenon near the Fermi level,which indicates that Cr 3d and O 2p orbitals have intense hybrid effects.In addition,the spin electronic density results indicate that system magnetic moments are generated mainly by the unpaired 3d electrons of Cr atoms and are also related to the electron configuration.Moreover,the results of optical properties show that the obvious absorption peaks are observed in the far ultraviolet and the near ultraviolet regions and there is a red shift phenomenon in the ultraviolet region.These results indicate that the Cr-doped ZnO nanowires could be a promising dilute magnetic semiconductor material.
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