Electronic structure and magnetic properties of the N monodoping and (Li, N)-codoped ZnO

• Published in: Solid state communications Vol. 151; no. 8; pp. 619 - 623
• Main Authors: Chen, Yifei, Song, Qinggong, Yan, Huiyu, Yang, Xiong, Wei, Tong
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2011; Elsevier
• Subjects: A. Diluted magnetic semiconductors; B. First-principles; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Electronic structure; D. Magnetic moment; Electron density of states and band structure of crystalline solids; Electron states; Exact sciences and technology; Exchange and superexchange interactions; Magnetic properties and materials; Magnetic semiconductors; Magnetically ordered materials: other intrinsic properties; Physics; Semiconductor compounds; Studies of specific magnetic materials; B. First-principles; D. Magnetic moment; D. Electronic structure; A. Diluted magnetic semiconductors; Doping; Ferromagnetic materials; Magnetic moments; Electronic density of states; Lattice parameters; Semimagnetic semiconductors; Polarized spin; Density functional method; Impurity site; Zinc oxide; Nitrogen additions; Spin state; Codoping; Exchange interactions; Lithium additions; Magnetic properties
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2011.01.030

Using first-principles calculations based on density functional theory, we investigated systematically the electronic structures and magnetic properties of N monodoping and (Li, N) codoping in ZnO. The results indicate that monodoping of N in ZnO favors a spin-polarized state with a magnetic moment of 0.95 μ B per supercell and the magnetic moment mainly comes from the unpaired 2 p electrons of N and O atoms. In addition, it was found that monodoping of N in ZnO is a weak ferromagnet and it is the spin-polarized O atoms that mediate the ferromagnetic exchange interaction between the two N atoms. Interestingly, by Li substitutional doping at the cation site (Li Zn), the ferromagnetic stability can be increased significantly and the formation energy can be evidently reduced for the defective system. Therefore, we think that the enhancement of ferromagnetic stability should be attributed to the accessorial holes and the lower formation energy induced by Li Zn doping. ► N monodoped ZnO favors spin-polarized state with a magnetic moment of 0.95 μ B per supercell. ► The magnetic moment mainly comes from the unpaired 2 p electrons of N and O atoms. ► The monodoping of N in ZnO is a weak ferromagnet. ► Spin-polarized O atoms mediate ferromagnetic exchange interaction between two N atoms. ► Ferromagnetic (FM) stability can be increased by replacing a Zn with a Li (Li Zn). ► The enhancement of FM stability should be attributed to the accessorial holes and the lower formation energy induced by Li Zn.