https://doi.org/10.1051/epjap/2015150081
Effect of oxygen vacancy and zinc interstitial on the spontaneous polarization of wurtzite ZnO: maximally localized Wannier functions analysis
1
Department of Applied Physics and the MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an, Shaanxi
710049, P.R. China
2
Department of Physics, Xi’an Jiaotong University City College, Xi’an, Shaanxi
710018, P.R. China
a e-mail: hgye@mail.xjtu.edu.cn
Received:
7
February
2015
Revised:
29
March
2015
Accepted:
2
April
2015
Published online:
19
May
2015
First-principles calculations are employed to obtain the maximally localized Wannier functions of wurtzite ZnO with O vacancy and Zn interstitial. Through analyzing the shape of Wannier functions and the distribution of Wannier function centers, the influence of O vacancy and Zn interstitial in different charge states on the spontaneous polarization are investigated. We found that polarization appears in 
010 and [20] orientations when the defects are charged, and the absolute polarization value will get larger as the defect charge state increases. Neutral O vacancy decreases the spontaneous polarization along the [0 0 0 1] direction. For O vacancy in +1 and +2 charge states, an additional electronic field is introduced, and it results in a dramatic change in the electronic structure, which reverses the polarization. However, in the case of Zn interstitial in +2 charge state, we find that it is the ionic relaxation that plays a dominant role in the polarization reversal.
© EDP Sciences, 2015
