Daily Overview: Today’s highlight focuses on an in-depth understanding of the electronic structure of hybrid Ruddlesden–Popper nickelates. In Ref. [1], the authors employ DFT + dynamical mean-field theory to systematically investigate the effects of epitaxial strain on the normal-state electronic structure, quasiparticle renormalization, Fermi surface, and magnetic correlations of the bilayer nickelate La₃Ni₂O₇. They find that the Ni 3d bands exhibit pronounced orbital-selective renormalization and strong incoherence, with the x²−y² and 3z²−r² states approaching orbital-selective localization. The electronic properties of this system are highly sensitive to in-plane strain: tensile strain and moderate compressive strain enhance magnetic correlations, whereas at a large compressive strain of approximately −4% a Lifshitz transition occurs, in which the γ Fermi surface sheet associated with the shallow bonding Ni 3z²−r² flat band disappears and the magnetic correlations drop sharply, suggesting that superconductivity may be suppressed. These results support the picture that the spin/charge density wave stripe instability is driven by Fermi surface nesting and indicate that pressure and strain can effectively tune spin–charge density wave order and enhance spin fluctuations. arXiv submission processing window: 2026-08-18 00:00 to 2026-08-18 00:00 UTC.
1. Electronic structure and magnetic correlations in the epitaxially strained bilayer nickelate La$_3$Ni$_2$O$_{7}$
- Relevance Score:
5.7244 - Authors: I. V. Leonov
- Link: https://arxiv.org/abs/2608.14810
- Paper page: Electronic structure and magnetic correlations in the epitaxially strained bilayer nickelate La₃Ni₂O₇
Summary: Using DFT combined with dynamical mean-field theory, we investigate the effects of electronic correlations and epitaxial strain on the normal-state electronic structure, quasiparticle renormalization, Fermi surface, and magnetic correlations of the bilayer Ruddlesden-Popper nickelate La3Ni2O7. The results show that the Ni 3d bands exhibit pronounced orbital-selective renormalization and strong incoherence, with the Ni x2−y2 and 3z2−r2 states approaching orbital-selective localization. The electronic properties are highly sensitive to in-plane strain: tensile strain and moderate compressive strain up to about −2% significantly enhance magnetic correlations, whereas at a large compressive strain of about −4% the system undergoes a Lifshitz transition in which the γ Fermi surface sheet disappears. This sheet is associated with an almost fully occupied, shallow bonding Ni 3z2−r2 flat band and its disappearance leads to a sharp decrease in magnetic correlations, implying that superconductivity is suppressed. Overall, the results support the picture that spin/charge density wave stripe instability is driven by Fermi surface nesting and indicate that pressure and strain can effectively tune spin-charge density wave order, thereby enhancing spin fluctuations.