Ferroaxial transitions in glaserite-type compounds; Database screening, phonon calculations, and experimental verification

山岸 茂直*; 林田 健志*; 三澤 竜介*; 木村 健太*; 萩原 雅人   ; 村田 智城*; 廣瀬 左京*; 木村 剛*

Yamagishi, Shigetada*; Hayashida, Takeshi*; Misawa, Ryusuke*; Kimura, Kenta*; Hagihara, Masato; Murata, Tomoki*; Hirose, Sakyo*; Kimura, Tsuyoshi*

In recent years, ferroaxial order is discussed as a new class of ferroic states [1,2]. This order is a structural order characterized by a partial rotational distortion, which was initially introduced by R.D. Johnson et al. in 2011 [1]. It has been attracting increased interests because of its potential for unconventional physical phenomena and new functionalities such as transverse responses in which input external fields induce output conjugate physical quantities along the perpendicular direction [3]. However, only a few ferroaxial materials have been reported to date, (e.g., NiTiO [4,5] and RbFe(MoO) [5]). In this work, we sought new ferroaxial materials by formula-based screening using a regular expression search and the symmetry detection algorithm. As a result, we found that a glaserite- type compound, KZr(PO) , is one of the promising candidates for ferroaxial materials. Furtheremore, our ab initio phonon calculations suggested that this compound undergoes a ferroaxial transition. Experimentally, by the structural analysis using neutron powder diffraction measurements, we demonstrated that KZr(PO) shows a ferroaxial transition at about 700 K. The ferroaxial nature of KZr(PO) was further confirmed by the observation of its domain structures using a linear electrogyration effect, that is, optical rotation in proportion to an applied electric field [6]. In this presentation, we will provide details of the database screening and the experiments. [1] R. D. Johnson et al., Phys. Rev. Lett. 107, 137205 (2011). [2] J. Hlinka et al., Phys. Rev. Lett. 116, 17 (2016). [3] S.-W. Cheong et al., npj Quantum Mater. 6, 58 (2021). [4] T. Hayashida et al., Nat. Commun. 11, 4582 (2020). [5] T. Hayashida et al., Phys. Rev. Mater. 5, 124409 (2021). [6] S. Yamagishi et al., Chem. Mater. 35, 747 (2023).