Pressure-induced Jahn–Teller switch in the homoleptic hybrid perovskite [(CH3)2NH2]Cu(HCOO)3: orbital reordering by unconventional degrees of freedom. Issue 25 (14th June 2021)

• Record Type: Journal Article
• Authors: Scatena, Rebecca; Andrzejewski, Michał; Johnson, Roger D.; Macchi, Piero
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 25(2021)
• Page Start: 8051
• Page End: 8056
• Publication Date: 2021-06-14
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1tc01966j
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Unconventional octahedral tilts unique to the coordination polymer perovskites support a high-pressure structural phase transition in [(CH3 )2 NH2 ]Cu(HCOO)3, which results in Jahn–Teller axis directional switching and orbital reordering. Abstract : Through in situ, high-pressure X-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3 )2 NH2 ]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct from previously reported Jahn–Teller switching in coordination polymers, which required at least two different ligands that crystallize in a reverse spectrochemical series. We show that the orbital reordering phase transition in [(CH3 )2 NH2 ]Cu(HCOO)3 is instead primarily driven by unconventional octahedral tilts and shifts in the framework, and/or a reconfiguration of A-site cation ordering. These structural instabilities are unique to the coordination polymer perovskites, and may form the basis for undiscovered orbital reorientation phenomena in this broad family of materials.