Structural phase transitions in a new LiNbO3-type ferroelectric-like \2018metal\2019

Ferroelectric metals combining ferroelectricity and metallicity two seemingly mutually exclusive properties in one system, was proposed over 50 years old and was revitalized by the recent discovery of the first unambiguous polar metal LiOsO3 with LiNbO3-type structure. A continuos structural phase transition from centrosymmetric to non-centrosymmetric group is considered as one criterion of ferroelectric metal. We successfully synthesized a novel LiNbO3-type oxide LiMoO3 using high pressure method. Neutron powder diffraction would be helpful in determining Li positions and occupancy more precisely than synchrotron X-ray diffraction owing to the higher sensitivity of Li to scattering of neutrons. To allow us to solve the crystal structure and phase transition, we propose a variable-temperature (1.5 - 300 K) neutron powder diffraction experiment to be performed on WISH.