A recent J.Am.Chem.Soc. Article (DOI: 10.1021/jacs.3c13094) details a pressure-temperature (P-T) phase diagram for the Ruddlesden-Popper bilayer nickelate La3Ni2O7 (LNO-2222) using synchrotron X-ray diffraction. This study identifies a phase transition from Amam (#63) to Fmmm (#69) within the temperature range of 104 K to 120 K under initial pressure and attributes the I4/mmm (#139) space group to the structure responsible for the superconductivity of LNO-2222. Herein, we examine the temperature-dependent structural evolution of LNO-2222 single crystals at ambient pressure. Contrary to symmetry increase and the established Amam-Fmmm phase boundary, we observe an enhancement in the Cmcm reflections as temperature decreases. This work not only establishes a benchmark method for single crystal structure studies of LNO-2222 using laboratory X-rays, but also enhances the understanding of the complex crystallographic behavior of this system, contributing insights to further experimental and theoretical explorations.
@article{arxiv.2405.08802,
title = {Temperature-dependent Structural Evolution of Ruddlesden-Popper Bilayer Nickelate La$_3$Ni$_2$O$_7$},
author = {Haozhe Wang and Haidong Zhou and Weiwei Xie},
journal= {arXiv preprint arXiv:2405.08802},
year = {2024}
}