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arXiv · 2111.02511

Soft X-ray Spectroscopy of Low-Valence Nickelates

M. Hepting·M. P. M. Dean·W. S. Lee
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Abstract

Low-valence nickelates $-$ including infinite-layer (IL) and trilayer (TL) compounds $-$ are longstanding candidates for mimicking the high-temperature superconductivity of cuprates. A recent breakthrough in the field came with the discovery of superconductivity in hole-doped IL nickelates. Yet, the degree of similarity between low-valence nickelates and cuprates is the subject of a profound debate for which soft x-ray spectroscopy experiments at the Ni $L$- and O $K$-edge provided critical input. In this review, we will discuss the essential elements of the electronic structure of low-valance nickelates revealed by x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS). Furthermore, we will review magnetic excitations observed in the RIXS spectra of IL and TL nickelates, which exhibit characteristics that are partly reminiscent of those of cuprates.

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M. Hepting, M. P. M. Dean, W. S. Lee. 2021-11-03. Soft X-ray Spectroscopy of Low-Valence Nickelates. https://doi.org/10.3389/fphy.2021.808683

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