FAPbI3_tetragonal&cubic

Initial structure of FAPbI3 of cubic phase was obtained through CIF file reported in previous report. While for tetragonal phase, no such CIF file could be found. Thus, we directly substitute Cs+ for FA+ in tetragonal phase CsPbI3, and then the resulting structure was relaxed through DFT calculation for the most stable structure. According to the usually inaccurate position of light element, we only apply structure relaxation calculation on FA+ while the Pb2+ and I- remain still.Structure relaxation and band-structure calculations are performed with plane-wave pseudopotential approach implemented in DS-PAW package. The exchange-correlation effects are concerned by PBE functional. The plane-wave cutoff energy was set to be 300.0 eV. The k-point number we set to be 5 × 5 × 5 for cubic phase and 4 × 4 × 5 for tetragonal phase respectively. Due to the heavy atom contained in perovskite materials, spin orbit coupling is included in DFT calculation for describing the real physical scenario.

立方相甲脒铅碘(FAPbI₃)的初始结构通过既往研究报道的晶体学信息文件(CIF)获取。而四方相FAPbI₃暂无可用的此类CIF文件，因此我们直接以铯离子(Cs⁺)取代四方相铯铅碘(CsPbI₃)中的甲脒离子(FA⁺)，随后通过密度泛函理论(DFT)计算对所得结构进行弛豫以得到最稳定构型。考虑到轻元素的原子位置通常难以精准确定，我们仅对FA⁺进行结构弛豫计算，而铅离子(Pb²⁺)与碘离子(I⁻)的位置保持固定。结构弛豫与能带结构计算均通过DS-PAW软件包所实现的平面波赝势方法完成，交换关联效应采用PBE泛函进行描述，平面波截断能设置为300.0 eV。立方相与四方相的k点网格分别设置为5×5×5与4×4×5。鉴于钙钛矿材料中含有重原子，为更精准地还原真实物理场景，我们在DFT计算中纳入了自旋轨道耦合效应。

搜集汇总

背景与挑战

背景概述

该数据集提供了FAPbI3钙钛矿材料的四方相和立方相初始结构，其中立方相基于已有CIF文件构建，四方相通过替换CsPbI3中的Cs+为FA+并经DFT弛豫获得。数据集特点包括：结构弛豫仅针对FA+离子，以处理轻元素位置不准确问题；计算采用DS-PAW软件包和PBE泛函，并包含自旋轨道耦合以准确描述含重原子的物理场景。