2025/12/11 by Shaikh, Monirul, Buvaneswaran, Sathiyamoorthy, Bhat, Asif Latief +2
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2512.10647
Wide band gap materials are particularly relevant at high temperatures. The band gap shrinkage at higher temperatures prevents device applications with narrow band gap semiconductors. Considering α-phase strontium cyanurate as a prototype structure, we identify a group of metal-organic frameworks (MOFs) that exhibit ultra-wide band gaps ranging from 5.5 to 5.7 eV. Recently, a strontium cyanurate compound was found to undergo a phase transition from a high-symmetry β-phase to a low-symmetry ferroelectric α-phase when the temperature was reduced. In the present study, utilizing group theory techniques, we unravel that a zone-center Γ2- phonon mode modifies our structures from high-symmetry β-phase to a low-symmetry α-phase for A3(O3C3N3)2 MOFs with A = Mg, Ca, Sr, and Ba. We implement first-principles calculations to investigate structural, ferroelectric, and optical properties of these compounds in α-phase. The switching barriers between bistable polar states are also estimated. Further, to realize their feasibility, we examine the dynamical and thermal stabilities for all of these MOFs.