Electronic structure of the alternating monolayer-trilayer phase of La3Ni2O7

Abstract

Recent studies of La${}_3$Ni${}_2$O${}_7$ have identified a bilayer (2222) structure and an unexpected alternating monolayer-trilayer (1313) structure, both of which feature signatures of superconductivity near 80 K under high pressures. Using angle-resolved photoemission spectroscopy, we measure the electronic structure of 1313 samples. In contrast to the previously studied 2222 structure, we find that the 1313 structure hosts a flat band with a markedly different binding energy, as well as an additional electron pocket and band splittings. By comparison to local-density approximation calculations, we find renormalizations of the Ni-$d_{z^2}$ and Ni-$d_{x^2-y^2}$ derived bands to be about 5 to 7 and about 4 respectively, suggesting strong correlation effects. These results reveal important differences in the electronic structure brought about by the distinct structural motifs with the same stoichiometry. Such differences may be relevant to the putative high temperature superconductivity.

Version 2: Improved data quality of the small electron pocket at the zone center ($\epsilon$ band). Also, observations of multilayer splitting effects in the flat band ($\gamma$ and $\delta$ bands) and in the large cuprate-like pockets ($\beta$ bands). Band structure calculations now use LDA instead of LDA+U. Main text: 7 pages, 3 figures. SM: 9 pages, 6 figures

Cited by in corpus (2)

• Ambient-pressure superconductivity onset above 40 K in bilayer nickelate ultrathin films
• Absence of phonon-mediated superconductivity in La${}_3$Ni${}_2$O${}_7$ under pressure