Electronic and Magnetic Properties of Ni-Doped Zinc-Blende ZnO: A First-Principles Study.

Suqin Xue,Shuili Zhang,Tingting Shao,Xiaoyang Wang,Fuchun Zhang

doi:10.3390/nano8050281

Abstract

The electronic structure, band structure, density of state, and magnetic properties of Ni-doped zinc-blende (ZB) ZnO are studied by using the first-principles method based on the spin-polarized density-functional theory. The calculated results show that Ni atoms can induce a stable ferromagnetic (FM) ground state in Ni-doped ZB ZnO. The magnetic moments mainly originate from the unpaired Ni 3d orbitals, and the O 2p orbitals contribute a little to the magnetic moments. The magnetic moment of a supercell including a single Ni atom is 0.79 μB. The electronic structure shows that Ni-doped ZB ZnO is a half-metallic FM material. The strong spin-orbit coupling appears near the Fermi level and shows obvious asymmetry for spin-up and spin-down density of state, which indicates a significant hybrid effects from the Ni 3d and O 2p states. However, the coupling of the anti-ferromagnetic (AFM) state show metallic characteristic, the spin-up and spin-down energy levels pass through the Fermi surface. The magnetic moment of a single Ni atom is 0.74 μB. Moreover, the results show that the Ni 3d and O 2p states have a strong p-d hybridization effect near the Fermi level and obtain a high stability. The above theoretical results demonstrate that Ni-doped zinc blende ZnO can be considered as a potential half-metal FM material and dilute magnetic semiconductors.

Highlights

Diluted magnetic semiconductors (DMSs) are a new type of semiconductor material which obtain FM properties by doping 3d transition-metal atoms
For configuration III and configuration IV, the calculated lattice constants showed a good consistency with the 2 × 2 × 2 supercell, and four configurations of Ni-doped ZB ZnO were approximate to the experimental value [23], the calculated relative error was less than 2%
The electronic structure and coupling mechanism of Ni-doped ZB ZnO are investigated by using the spin polarization approach based on first-principles density functional theory (DFT)

Summary

Introduction

Diluted magnetic semiconductors (DMSs) are a new type of semiconductor material which obtain FM properties by doping 3d transition-metal atoms. They have been investigated extensively because of their potential usage of both the charge and spin properties of freedom of carriers in spintronic devices. Sato et al [11] have researched transition-metal atoms (Mn, V, Cr, Fe, Co, Ni) doped ZnO materials through first-principle calculations, and the results show that the doping system has FM properties. Ueda et al [12] have successfully prepared 3d transition-metal-doped ZnO thin film materials, the results show that the Curie temperature is greater than 280 K. Yin et al have reported that no FM feature has been observed in Zn1−xNixO nano-materials [22]

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Conclusion