A defining signature of strongly correlated electronic systems is the existence of competing phases with similar ground state energies, resulting in a rich phase diagram. While in the recently discovered nickelate superconductors, a high antiferromagnetic exchange energy has been reported, which implies the existence of strong electronic correlations, signatures of competing phases have not yet been observed. Here, we uncover a charge order (CO) in infinite-layer nickelates La1-xSrxNiO2 using resonant x-ray scattering across the Ni L-edge. In the parent compound, the CO arranges along the Ni-O bond direction with an incommensurate wave vector (0.344+/-0.002, 0) r.l.u., distinct from the stripe order in other nickelates which propagates along a direction 45 degree to the Ni-O bond. The CO resonance profile indicates that CO originates from the Ni 3d states and induces a parasitic charge modulation of La electrons. Upon doping, the CO diminishes and the ordering wave vector shifts toward a commensurate value of 1/3 r.l.u., indicating that the CO likely arises from strong correlation effects and not from Fermi surface nesting.
@article{arxiv.2112.02484,
title = {A Broken Translational Symmetry State in an Infinite-Layer Nickelate},
author = {Matteo Rossi and Motoki Osada and Jaewon Choi and Stefano Agrestini and Daniel Jost and Yonghun Lee and Haiyu Lu and Bai Yang Wang and Kyuho Lee and Abhishek Nag and Yi-De Chuang and Cheng-Tai Kuo and Sang-Jun Lee and Brian Moritz and Thomas P. Devereaux and Zhi-Xun Shen and Jun-Sik Lee and Ke-Jin Zhou and Harold Y. Hwang and Wei-Sheng Lee},
journal= {arXiv preprint arXiv:2112.02484},
year = {2022}
}