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

Conflicting theoretical scenarios for infinite-layer nickelate superconductors have been hotly debated, particularly regarding whether only a single Ni-<a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>3</a:mn><a:msub><a:mi>d</a:mi><a:mrow><a:msup><a:mi>x</a:mi><a:mn>2</a:mn></a:msup><a:mo>−</a:mo><a:msup><a:mi>y</a:mi><a:mn>2</a:mn></a:msup></a:mrow></a:msub></a:mrow></a:math> band is relevant at low energies besides electron pockets or whether multiorbital physics including Ni-<b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mn>3</b:mn><b:msub><b:mi>d</b:mi><b:msup><b:mi>z</b:mi><b:mn>2</b:mn></b:msup></b:msub></b:mrow></b:math> 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 quasiparticle bands, supporting the first scenario. Our key findings further suggest that the “waterfalls” observed in ARPES might emerge from the quasiparticle-to-Hubbard-band crossover, and that additional spectral weight close to the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mi>A</c:mi></c:math> pocket likely originates from the Ni-<d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mn>3</d:mn><d:msub><d:mi>d</d:mi><d:mrow><d:mi>x</d:mi><d:mi>y</d:mi></d:mrow></d:msub></d:mrow></d:math> orbital. Published by the American Physical Society 2024