Antiferromagnetic quantum critical point in LaNiO₃

March 31, 2020

In a study published in Nature Communications, researchers observed a quantum critical point in a perovskite nickelate. At this anomalous point, the material displays unique transport and thermodynamic properties.

Left: resistivity exponent versus temperature as compared to a theory of QCP fluctuations with disorder. Right: phase diagram showing proximity of LaNiO₃ to a quantum critical point.

Scientific Achievement

Scientists observed an antiferromagnetic quantum critical point (QCP) in high-purity LaNiO₃.

Significance and Impact

At a QCP, fluctuations of the order parameter can have a profound influence on the properties of a material, such as a breakdown of the Landau Fermi liquid, leading to a “strange metal” with anomalous transport and thermodynamic properties.

Research Details

LaNiO₃ thin films with unprecedented high purities are prepared using oxide molecular beam epitaxy.
Transport measurements reveal a linear dependence of the resistivity with temperature over nearly a decade for T ≤ 1.1 K. Fermi liquid behavior is restored in a large magnetic field when quantum critical fluctuations are suppressed.
A series of samples with varying levels of disorder show the predicted behavior of the resistivity near a QCP as a function of temperature, as well as a magnetoresistance arising from scattering by local magnetic moments.

DOI: 10.1038/s41467-020-15143-w

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