Even J, Pedesseau L, Katan C
Université Européenne de Bretagne INSA, FOTON UMR 6082, 35708 Rennes, France.
Phys Chem Chem Phys. 2014 May 14;16(18):8697-8. doi: 10.1039/c3cp55006k.
Yun Wang et al. used density functional theory (DFT) to investigate the orthorhombic phase of CH3NH3PbI3, which has recently shown outstanding properties for photovoltaic applications. Whereas their analysis of ground state properties may represent a valuable contribution to understanding this class of materials, effects of spin-orbit coupling (SOC) cannot be overlooked as was shown in earlier studies. Moreover, their discussion on optical properties may be misleading for non-DFT-experts, and the nice agreement between experimental and calculated band gap is fortuitous, stemming from error cancellations between SOC and many-body effects. Lastly, Bader charges suggest potential problems during crystal structure optimization.
王云等人使用密度泛函理论（DFT）研究了CH3NH3PbI3的正交相，该相最近在光伏应用中表现出优异的性能。虽然他们对基态性质的分析可能对理解这类材料有重要贡献，但正如早期研究所表明的，自旋轨道耦合（SOC）的影响不能被忽视。此外，他们对光学性质的讨论可能会误导非DFT专家，并且实验和计算的带隙之间的良好一致性是偶然的，源于SOC和多体效应之间的误差抵消。最后，巴德电荷表明在晶体结构优化过程中可能存在问题。
