Hallmark of strong electronic correlations in LaNiO$_3$: photoemission kink and broadening of fully occupied bands

TL;DR

This paper demonstrates that electronic correlations in LaNiO$_3$ cause observable features in photoemission spectra, such as velocity renormalization, dispersion kinks, and band broadening, which are accurately reproduced by combined DFT and DMFT calculations.

Contribution

It provides a quantitative explanation of photoemission features in LaNiO$_3$ using advanced theoretical methods, highlighting the role of correlations in filled bands.

Findings

Correlation effects cause velocity renormalization and dispersion kinks.

Broadening of occupied bands is due to electronic correlations.

Theoretical calculations match experimental photoemission data.

Abstract

Recent angular-resolved photoemission experiments on LaNiO$_3$ reported a renormalization of the Fermi velocity of $e_g$ quasiparticles, a kink in their dispersion at $ -0.2$ eV and a large broadening and weakened dispersion of the occupied $t_{2g}$ states. We show here that all these features result from electronic correlations and are quantitatively reproduced by calculations combining density-functional theory and dynamical mean-field theory. The importance and general relevance of correlation effects in filled bands coupled by inter-orbital interactions to a partially-filled band are pointed out.