The presence of ferroelectricity in hexagonal (h-)InMnO3 has been highly under debate. The results of our comprehensive experiments of low-temperature (T) polarization, TEM and HAADF-STEM on well-controlled h-InMnO3 reveal that the ground state is ferroelectric with P6_3cm symmetry, but a non-ferroelectric P-3c1 state exists at high T, and can be quenched to room T. We also found that the ferroelectric P6_3cm state of h-InMnO3 exhibits the domain configuration of topological vortices, as has been observed in h-REMnO3 (RE=rare earths).
@article{arxiv.1303.5606,
title = {Is hexagonal InMnO3 ferroelectric?},
author = {F. -T. Huang and X. Wang and Y. S. Oh and K. Kurushima and S. Mori and Y. Horibe and S. -W. Cheong},
journal= {arXiv preprint arXiv:1303.5606},
year = {2016}
}