Electronic correlations and partial gap in the bilayer nickelate La₃Ni₂O₇

Summary

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-d_3z2-r2orbital is removed due to the transition at T ∗. Our experimental results provide pivotal information for understanding the transition at T ∗ and superconductivity in La₃Ni₂O₇.

Materials

• La₃Ni₂O₇

Methods

• optical spectroscopy
• optical conductivity

Keywords

• electronic correlations
• mott phase
• drude components
• non fermi liquid behavior
• fermi surface
• ni d3z2 r2 orbital

Highlights

• Optical study shows electronic correlations and partial gap in bilayer nickelate La₃Ni₂O₇.
• Pivotal information for understanding the transition at T∗ and superconductivity.

Conclusions

• 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.
• The Fermi surface dominated by the Ni-d3z2-r2 orbital is removed due to the transition at T∗.

Main claims

Not available in this batch.

Workflow

Not available in this batch.