论文标题
碘化甲基铵铅中的铁电性丢失
Missed ferroelectricity in methylammonium lead iodide
论文作者
论文摘要
作为相关的有机卤化钙钛矿，碘化甲基铵铅铅铅最近成为光伏应用的特别有吸引力的材料。其吸引力的特性的起源有时被分配给其潜在的铁电特征，但是这仍然是一个激烈辩论的话题。在这里，我们从第一原理计算中合理化了甲基铵极性分子的空间排列如何逐渐受到与无机框架结合的趋势与碘二曲旋转的趋势之间的微妙相互作用，而这些相互作用是在perovskite结构上固有的。在室温下观察到的四方相位的四方相是副型。我们表明，先验的人应该成为铁电，但是碘八面体旋转将系统驱动到抗多极的骨质骨基态，从而使其成为缺失的铁电。
Methylammonium lead iodide, as related organometal halide perovskites, emerged recently as a particularly attractive material for photovoltaic applications. The origin of its appealing properties is sometimes assigned to its potential ferroelectric character, which remains however a topic of intense debate. Here, we rationalize from first-principles calculations how the spatial arrangement of methylammonium polar molecules is progressively constrained by the subtle interplay between their tendency to bond with the inorganic framework and the appearance of iodine octahedra rotations inherent to the perovskite structure. The disordered tetragonal phase observed at room temperature is paraelectric. We show that it should a priori become ferroelectric but that iodine octahedra rotations drive the system toward an antipolar orthorhombic ground state, making it a missed ferroelectric.
