Electronic Correlations and Hund's Rule Coupling in Trilayer Nickelate La4Ni3O10

TL;DR

This paper investigates the role of electronic correlations and Hund's rule coupling in La4Ni3O10, revealing their orbital- and layer-dependent effects and their influence on the material's electronic structure under pressure.

Contribution

It provides a detailed theoretical analysis of electronic correlations in La4Ni3O10, highlighting the importance of Hund's rule coupling and crystal-field effects, which were not fully understood before.

Findings

Spectral functions match experimental ARPES data at ambient pressure

Electronic correlations are orbital- and layer-dependent under pressure

Hund's rule coupling influences the strength of electronic correlations

Abstract

Trilayer Ruddlesden-Popper phase La4Ni3O10 has been observed with Tc of about 30 K at high pressure in recent experiment, which further expanded the family of nickelate superconductors. In this study, we explored the effects of electronic correlations in La4Ni3O10 using density function theory plus dynamical mean-field theory at ambient and high pressures. Our derived spectral functions and Fermi surface of ambient pressure phase are nicely consistent with the experimental results by angle-resolved photoemission spectroscopy, which emphasized the importance of electronic correlations in La4Ni3O10. We also found the electronic correlations in pressured La4Ni3O10 are both orbital-dependent and layer-dependent due to the presence of Hund's rule coupling. There is a competition between the Hund's rule coupling and the crystal-field splitting, and therefore the Ni-O layers with weaker crystal-field splitting energy would have stronger electronic correlations.