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arXiv · 2111.13668

Magnetic correlations in infinite-layer nickelates: an experimental and theoretical multi-method study

R. A. Ortiz·P. Puphal·M. Klett·F. Hotz·R. K. Kremer·H. Trepka·M. Hemmida·H. -A. Krug von Nidda·M. Isobe·R. Khasanov·H. Luetkens·P. Hansmann·B. Keimer·T. Schäfer·M. Hepting
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Abstract

We report a comprehensive study of magnetic correlations in LaNiO$_{2}$, a parent compound of the recently discovered family of infinite-layer (IL) nickelate superconductors, using multiple experimental and theoretical methods. Our specific heat, muon-spin rotation ($\mu$SR), and magnetic susceptibility measurements on polycrystalline LaNiO$_{2}$ show that long-range magnetic order remains absent down to 2 K. Nevertheless, we detect residual entropy in the low-temperature specific heat, which is compatible with a model fit that includes paramagnon excitations. The $\mu$SR and low-field static and dynamic magnetic susceptibility measurements indicate the presence of short-range magnetic correlations and glassy spin dynamics, which we attribute to local oxygen non-stoichiometry in the average infinite-layer crystal structure. This glassy behavior can be suppressed in strong external fields, allowing us to extract the intrinsic paramagnetic susceptibility. Remarkably, we find that the intrinsic susceptibility shows non-Curie-Weiss behavior at high temperatures, in analogy to doped cuprates that possess robust non-local spin fluctuations. The distinct temperature dependence of the intrinsic susceptibility of LaNiO$_{2}$ can be theoretically understood by a multi-method study of the single-band Hubbard model in which we apply complementary cutting-edge quantum many-body techniques (dynamical mean-field theory, cellular dynamical mean-field theory and the dynamical vertex approximation) to investigate the influence of both short- and long-ranged correlations. Our results suggest a profound analogy between the magnetic correlations in parent (undoped) IL nickelates and doped cuprates.

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R. A. Ortiz, P. Puphal, M. Klett, F. Hotz, R. K. Kremer, H. Trepka, M. Hemmida, H. -A. Krug von Nidda, M. Isobe, R. Khasanov, H. Luetkens, P. Hansmann, B. Keimer, T. Schäfer, M. Hepting. 2021-11-26. Magnetic correlations in infinite-layer nickelates: an experimental and theoretical multi-method study. https://doi.org/10.1103/physrevresearch.4.023093

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