Wiktor Julia, Rothlisberger Ursula, Pasquarello Alfredo
Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.
Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.
J Phys Chem Lett. 2017 Nov 16;8(22):5507-5512. doi: 10.1021/acs.jpclett.7b02648. Epub 2017 Oct 31.
We carry out first-principles calculations of band gaps of cubic inorganic perovskites belonging to the class CsBX, with B = Pb, Sn and X = Cl, Br, I. We use the quasi-particle self-consistent GW method with efficient vertex corrections to calculate the electronic structure of the studied materials. We demonstrate the importance of including the higher-lying core and semicore shells among the valence states. For a meaningful comparison with experimental values, we account for thermal vibrations and disorder through ab initio molecular dynamics. Additionally, we calculate the spin-orbit coupling at levels of theory of increasing accuracy and show that semilocal density functionals significantly underestimate these corrections. We show that all of these effects need to be properly included in order to obtain reliable predictions for the band gaps of halide perovskites.
我们对属于CsBX类的立方无机钙钛矿的带隙进行了第一性原理计算，其中B = Pb、Sn，X = Cl、Br、I。我们使用具有高效顶点修正的准粒子自洽GW方法来计算所研究材料的电子结构。我们证明了在价态中包含较高的核心和半核心壳层的重要性。为了与实验值进行有意义的比较，我们通过从头算分子动力学考虑了热振动和无序。此外，我们在精度不断提高的理论水平上计算了自旋轨道耦合，并表明半局域密度泛函显著低估了这些修正。我们表明，为了获得卤化物钙钛矿带隙的可靠预测，所有这些效应都需要适当地考虑在内。
