Infinite-layer (IL) nickelates have rapidly emerged as a new class of superconductors. However, due to the technical challenges of their topotactic synthesis, they have so far been realized primarily as thin films or polycrystalline powder samples, limiting comprehensive investigations of fundamental physical properties such as the lattice dynamics. Here, we present a time-of-flight inelastic neutron scattering study on a sample composed of a large number of co-aligned bulk crystals of the IL nickelate LaNiO2. We observe several dispersive phonon branches, which are in good agreement with lattice dynamical calculations based on density-functional perturbation theory. In addition, we compare the characteristics of selected LaNiO2 phonon modes to those of isostructural cuprate superconductors. Our findings provide a reference point for future experimental and theoretical efforts aimed at understanding the interplay between lattice dynamics and electronic properties in IL nickelates.
@article{arxiv.2509.03750,
title = {Lattice dynamics of the infinite-layer nickelate LaNiO$_2$},
author = {Shohei Hayashida and Vignesh Sundaramurthy and Wenfeng Wu and Pascal Puphal and Thomas Keller and Björn Fåk and Masahiko Isobe and Bernhard Keimer and Karsten Held and Liang Si and Matthias Hepting},
journal= {arXiv preprint arXiv:2509.03750},
year = {2025}
}