  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).
