Identification of Chiral Framework Distortions in Hybrid Organic-Inorganic Perovskites*

Hybrid organic-inorganic perovskites (HOIPs) have gained significant attention for their applications as promising functional materials, particularly as optoelectronics and photovoltaics due to their exceptional electronic and optical properties. This research focuses on the identification and description of chiral framework distortions within layered HOIP materials. Using group representation theory (GRT), we identify the irreducible space-group representations (irreps) whose order parameters are either capable of straining the unit cell or displacing one or more HOIP-framework atoms and provide physical descriptions of these order parameters. We then systematically examine the joint order parameters of sets of these irreps to identify those that yield chiral framework distortions.