Institut für Materialwissenschaft, Technische Universität Darmstadt, Petersenstrasse 32, D-64287 Darmstadt, Germany.
Phys Rev Lett. 2009 Dec 11;103(24):245501. doi: 10.1103/PhysRevLett.103.245501.
We present a comparative study of oxygen vacancies in In2O3, SnO2, and ZnO based on the hybrid-functional method within the density-functional theory (DFT). For In2O3 and SnO2, our results provide strong evidence of shallow donor states at oxygen vacancies. In comparison with the (semi)local exchange-correlation approximations in DFT, the hybrid-functional method strongly lowers the formation energy of the positive charge state and keeps that of the neutral state nearly intact. The trend is analyzed in terms of changes in lattice relaxation energies and in electron energy levels near the band gap. The existence of shallow donor states at oxygen vacancies and the consequent n-type conductivity are in line with experimental findings. The results invalidate some former theoretical interpretations based on standard DFT calculations.
我们基于密度泛函理论（DFT）中的杂化泛函方法，对 In2O3、SnO2 和 ZnO 中的氧空位进行了比较研究。对于 In2O3 和 SnO2，我们的结果提供了氧空位处浅施主态的有力证据。与 DFT 中的（半）局域交换关联近似相比，杂化泛函方法强烈降低了正电荷态的形成能，同时几乎保持了中性态的形成能不变。这一趋势可以从晶格弛豫能和能带隙附近电子能级的变化来分析。氧空位处浅施主态的存在以及由此产生的 n 型导电性与实验结果相符。这些结果否定了一些基于标准 DFT 计算的先前理论解释。
