Oxygen octahedral distortions, including tilts/rotations, deformations and off-centring in (layered) perovskites, have the key role in their numerous functional properties. Near the polar-centrosymmetric phase boundary in bi-layered perovskite Ca3 −xSrxTi2O7 with x≈1, we found the presence of abundant topological eight-state vortex-antivortex pairs, associated with four oxygen octahedral tilts at domains and another four different oxygen octahedral tilts at domain walls. Our discovery opens a new revenue to unveil realspace topological defects associated with the possible vector choices in one specific lattice mode.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics