Closing in on possible scenarios for infinite-layer nickelates: comparison of dynamical mean-field theory with angular-resolved photoemission spectroscopy

TL;DR

This study compares theoretical DFT+DMFT calculations with ARPES experiments on infinite-layer nickelates, finding strong agreement that supports a single-band low-energy physics scenario and providing insights into spectral features and orbital contributions.

Contribution

The paper demonstrates that DFT+DMFT accurately reproduces ARPES spectra, supporting a simplified single-band model and clarifying the origin of spectral features in nickelate superconductors.

Findings

Excellent agreement between DFT+DMFT and ARPES spectra.

Waterfalls in ARPES may result from Hubbard-band crossover.

Additional spectral weight near the A-pocket likely from Ni-3d_{xy} orbital.

Abstract

Conflicting theoretical scenarios for infinite-layer nickelate superconductors have been hotly debated, particularly regarding whether {only} a single Ni-3$d_{x^2-y^2}$ band is relevant at low energies besides electron pockets or whether multi-orbital physics including Ni-3$d_{z^2}$ is instead essential. The first scenario has emerged from density-functional theory plus dynamical mean-field theory (DFT+DMFT) calculations. Comparing the previous DFT+DMFT spectra to recent angular-resolved photoemission spectroscopy (ARPES) experiments, we find excellent agreement for both the Fermi surface and the strongly renormalized quasi-particle bands, supporting the first scenario. Our key findings further suggest that the "waterfalls" observed in ARPES might emerge from the quasi-particle--to--Hubbard-band crossover, and that additional spectral weight close to the $A$-pocket {likely} originates from the Ni-3$d_{xy}$ orbital.