Electronic correlations and partial gap in the bilayer nickelate La₃Ni₂O₇.

ABSTRACT: The discovery of superconductivity with a critical temperature of about 80 K in La₃Ni₂O₇ single crystals under pressure has received enormous attention. La₃Ni₂O₇ is not superconducting under ambient pressure but exhibits a transition at T ^∗ ≃ 115 K. Understanding the electronic correlations and charge dynamics is an important step towards the origin of superconductivity and other instabilities. Here, our optical study shows that La₃Ni₂O₇ features strong electronic correlations which significantly reduce the electron's kinetic energy and place this system in the proximity of the Mott phase. The low-frequency optical conductivity reveals two Drude components arising from multiple bands at the Fermi level. The transition at T ^∗ removes the Drude component exhibiting non-Fermi liquid behavior, whereas the one with Fermi-liquid behavior is barely affected. These observations in combination with theoretical results suggest that the Fermi surface dominated by the Ni- d3z2-r2 orbital is removed due to the transition at T ^∗. Our experimental results provide pivotal information for understanding the transition at T ^∗ and superconductivity in La₃Ni₂O₇.

SUBMITTER: Liu Z 

PROVIDER: S-EPMC11365989 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature