Faculty of Chemistry Laboratory of Thermodynamics and Molecular Modeling Universite des Sciences et de la Technologie Houari Boumediene BP 32, Al Alia 16111 Bab Ezzouar Algiers Algeria
Simulation, Modelling and Computer‐Aided Design ‐ Laboratory L5 National Institute for Research and Development in Microtechnologies (IMT) 126A, Erou Iancu Nicolae Street 077190 Bucharest Romania
New phase transitions driven by the soft mode condensation from the Pm3m structure to related subgroup variants are predicted for CsPbBr3 from DFT calculations, performed by Raouia Ben Sadok and co‐workers (see article number 2000289). The Pb2+ cation has only a small contribution to the structural distortions, which leaves an important role to Br– and Cs+ displacements in the structure stabilization. The ferroelectric distortion is found less favorable than the antiferrodistortive one, where the out‐of‐phase rotations of the PbBr6 octahedra may determine more stable structures than the in‐phase rotations. Nevertheless, the polar structure Pmc21 appears to be a candidate as ground state. All predicted structures show semiconductor character, with the band gap increasing when increasing the Pb–Br bond length and the angle of rotation of the PbBr6 octahedra. The optical dielectric constant and Born effective charges show low sensitivity to unit cell volume.
中文翻译：
CsPbBr3的软声子模式驱动的新相变：密度泛函理论研究
由Raouia Ben Sadok及其同事进行的DFT计算可预测CsPbBr 3由Pm3m结构到相关亚组变体的软模式缩合驱动的新相变（请参见编号2000289）。铅2+阳离子只对结构扭曲，这让为BR起重要作用的小的贡献-和Cs +在结构稳定位移。发现铁电畸变不如反铁畸变畸变，反铁畸变是PbBr 6八面体的异相旋转可能比同相旋转更稳定的结构。尽管如此，极性结构Pmc2 1似乎是基态的候选者。所有预测的结构都显示出半导体特性，当增加Pb-Br键长度和PbBr 6八面体的旋转角度时，带隙增加。光学介电常数和Born有效电荷显示出对晶胞体积的低敏感性。
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