Institute for Research and Development of Photovoltaic Energy, UMR 7174 CNRS/EDF/ENSCP, 6 quai Watier, 78401 Chatou, France.
Phys Rev Lett. 2010 Apr 2;104(13):136401. doi: 10.1103/PhysRevLett.104.136401. Epub 2010 Mar 29.
We use hybrid functionals and restricted self-consistent GW, state-of-the-art theoretical approaches for quasiparticle band structures, to study the electronic states of delafossite Cu(Al,In)O2, the first p-type and bipolar transparent conductive oxides. We show that a self-consistent GW approximation gives remarkably wider band gaps than all the other approaches used so far. Accounting for polaronic effects in the GW scheme we recover a very nice agreement with experiments. Furthermore, the modifications with respect to the Kohn-Sham bands are strongly k dependent, which makes questionable the common practice of using a scissor operator. Finally, our results support the view that the low energy structures found in optical experiments, and initially attributed to an indirect transition, are due to intrinsic defects in the samples.
我们使用混合泛函和限制自洽 GW 方法，这是一种用于准粒子能带结构的最先进的理论方法，来研究 delafossite Cu(Al,In)O2 的电子态，它是第一种 p 型和双极性透明导电氧化物。我们表明，自洽 GW 近似给出的带隙明显大于迄今为止使用的所有其他方法。在 GW 方案中考虑极化子效应，我们与实验结果非常吻合。此外，与 Kohn-Sham 能带相比的修正强烈依赖于 k，这使得使用剪刀运算符的常见做法受到质疑。最后，我们的结果支持这样一种观点，即在光学实验中发现的低能结构，最初归因于间接跃迁，是由于样品中的本征缺陷造成的。
