Ferroaxial order of the monolayer ice in martyite
Abstract
Ice Ih, the most stable phase of water at ambient pressure, is a stacking of the honeycomb network of water molecules H2O. What if one layer of ice is exfoliated and confined to a two-dimensional (2D) sheet? Martyite Zn3(V2O7)(OH)2 2H2O, a mineral with the honeycomb lattice of H2O in the porous framework, is an ideal system for studying such monolayer ice. Due to the geometrical frustration and 2D nature, H2O molecules are dynamically disordered at room temperature. In this study, we reveal disorder-order transitions of H2O in martyite using single-crystal x-ray diffraction (XRD). The XRD results visualize the formation of hydrogen-bonded toroidal H2O hexamers, leading to the ferroaxial order below 200 K. Combined with the molecular dynamics simulations, we discuss the formation process of the H2O hexamers and how they compromise the molecular arrangement towards lower temperatures. Our results unveil the ground state of monolayer ice, a fundamental knowledge to understand the polymorphism of H2O.
Cite
@article{arxiv.2503.14018,
title = {Ferroaxial order of the monolayer ice in martyite},
author = {Toshihiro Nomura and Shunsuke Kitou and Junichi Komatsu and Kenichiro Koga and Takumi Hasegawa and Norio Ogita and Yuiga Nakamura and Hajime Ishikawa and Takeshi Yajima and Akira Matsuo and Maiko Kofu and Osamu Yamamuro and Zenji Hiroi and Yusuke Tomita and Taka-hisa Arima and Takasuke Matsuo},
journal= {arXiv preprint arXiv:2503.14018},
year = {2026}
}
Comments
7 pages, 4 figures, and 10 pages of supplemental materials