Intrinsic Spin Susceptibility and Pseudogaplike Behavior in Infinite-Layer LaNiO_{2}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Superconductivity in infinite-layer nickelates is a recent discovery, prompting comparisons with cuprates.
• The magnetic ground state of undoped infinite-layer nickelates remained elusive, despite prior magnetization studies suggesting Curie-Weiss-like behavior.

Purpose of the Study:

• To investigate the intrinsic spin susceptibility and magnetic ground state of infinite-layer LaNiO2.
• To clarify the magnetic properties of undoped infinite-layer nickelates using nuclear magnetic resonance (NMR).

Main Methods:

• $^{139}$La nuclear magnetic resonance (NMR) spectroscopy was employed.
• Temperature-dependent Knight shift and nuclear spin-lattice relaxation rate (1/T$_{1}$) measurements were performed down to 0.24 K.

Main Results:

• $^{139}$La NMR spectra showed no magnetic ordering or freezing, confirming a paramagnetic ground state.
• A pseudogap-like behavior was observed in temperature-dependent Knight shift and 1/T$_{1}$, contrasting with Curie-Weiss-like behavior.
• Scaling behavior between Knight shift and 1/T$_{1}$T was analyzed.

Conclusions:

• The paramagnetic ground state of LaNiO2 is unambiguously confirmed.
• The observed pseudogap-like behavior is consistent with findings in underdoped cuprates and iron-based superconductors.
• The results imply significant exchange interactions in infinite-layer nickelates, constraining theoretical models.