Searching for structural Goldstone-like modes in 4H-Sr1-xCaxMnO3

The recent discovery of exotic domain topologies in ferroelectric materials has ignited renewed interest in these systems. It is now of interest to identify new ferroelectrics in which such rich topological behaviours can be stabilised to acquire deeper fundamental understanding of how they form. We recently performed a high-resolution powder diffraction experiment at the ID22 beamline on the six-layer hexagonal polytype of BaTiO3, and we found that a structural Goldstone-like mode enables an unusual quasi-continuous domain texture to emerge at low temperatures. Our preliminary DFT calculations suggest similar Goldstone-like modes may be observed in other perovskite polytypes, and we now seek to validate this on an experimental basis by performing a high-resolution diffraction experiment at ID22 on the 4H-Sr1-xCaxMnO3 system. This represents a vital step in illustrating a generalisable mechanism by which exotic domain topologies may be stabilised in ferroelectric perovskites.