Heteroanionic oxysulfide perovskite compounds represent an emerging class of new materials allowing for a wide range of tunability in the electronic structure that could lead to a diverse spectrum of novel and improved functionalities. Unlike cation ordered double perovskites—where the origins and design rules of various experimentally observed cation orderings are well known and understood—anion ordering in heteroanionic perovskites remains a largely uncharted territory. In this contribution, we present and discuss insights that have emerged from our first-principles-based electronic structure analysis of a prototypical anion-ordered SrHf(O_0.5S_0.5)₃ oxysulfide chemistry, studied in all possible anion configurations allowed within a finite size supercell. We demonstrate that the preferred anion ordering is always an all-cis arrangement of anions around an HfO₃S₃ octahedron. As a general finding beyond the specific chemistry, the origins of this ordering tendency are traced back to a combined stabilization effect stemming from electronic, elastic, and electrostatic contributions. These qualitative notions are also quantified using state-of-the-art machine learning models. We further study the relative stability of the identified ordering as a function of A (Ca, Sr, Ba) and B (Ti, Zr, Hf) site chemistries and probe chemistry-dependent trends in the electronic structure and functionality of the material. Most remarkably, we find that the identified ground-state anion ordering breaks the inversion symmetry to create a family of oxysulfide ferroelectrics with a macroscopic polarization >30 μC/cm², exhibiting a significant promise for electronic materials applications.

杂阴离子氧硫化物钙钛矿化合物代表了新兴的一类新材料，可在电子结构中实现广泛的可调性，从而可带来各种新颖的功能和改进的功能。与阳离子有序的双钙钛矿不同（在实验中观察到的各种阳离子有序的起源和设计规则是众所周知的，而与之不同），杂阴离子钙钛矿中的阴离子有序仍然是一个未知领域。在这一贡献中，我们提出并讨论了基于原型原理的阴离子序SrHf（O _0.5 S _0.5）₃的基于第一原理的电子结构分析中得出的见解。氧硫化物化学，以有限尺寸的超级电池中允许的所有可能的阴离子构型进行研究。我们表明，优选的阴离子排序始终是一个清一色Ç我小号阴离子的周围布置的HfO ₃小号₃八面体。作为特定化学以外的一般发现，这种有序趋势的起源可追溯到源于电子，弹性和静电作用的综合稳定作用。这些定性概念也可以使用最新的机器学习模型进行量化。我们进一步研究了确定的有序排列的相对稳定性，该相对稳定性是A（Ca，Sr，Ba）和B（Ti，Zr，Hf）位点化学的函数，以及探针化学依赖性的材料电子结构和功能趋势。最引人注目的是，我们发现已确定的基态阴离子排序破坏了反演对称性，从而创建了一个宏观极化> 30μC/ cm ^2的氧硫化物铁电体家族，对电子材料应用具有重要的前景。