Hydrogen Bonding-Induced Symmetry Breaking and Spin Splitting in Hybrid Perovskites
December 14, 2024
Neutron and DFT-relaxed 2-BrPEA+ cations show notable discrepancies with XRD (top). Changes in H-bonds between equatorial I atoms at low temperature cause symmetry breaking (bottom).
Scientific Achievement
H-only DFT relaxation of 2D hybrid metal halide perovskite x-ray structure reveals organic templating effects, H-bond-mediated symmetry breaking and spin splitting.
Significance and Impact
This work provides a pathway to improve H-atom and H-bond analyses from x-ray data, enhancing control over symmetry-breaking for advanced material design.
Research Details
- Neutron diffraction precisely determines hydrogen positions.
- H-only DFT relaxation aligns x-ray H-atom positions with neutron data, correcting inaccuracies in x-ray-based H-bonding analysis.
- The structural transition rearranges H-bonds, shifts equatorial iodide atoms asymmetrically, increases overall asymmetry, and induces significant spin splitting (∆E > 30 meV).
Yi Xie, Gabrielle Koknat, Nicholas J. Weadock, Xiaoping Wang, Ruyi Song, Michael F. Toney, Volker Blum, and David B. Mitzi, “Hydrogen Bonding Analysis of Structural Transition-Induced Symmetry Breaking and Spin Splitting in a Hybrid Perovskite Employing a Synergistic Diffraction-DFT Approach”
Journal of the American Chemical Society 146 (32), 22509-22521 (2024)
DOI: 10.1021/jacs.4c06287
