Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Nickelates I
TT 5.6: Talk
Monday, March 18, 2024, 11:00–11:15, H 3007
Critical role of interlayer dimer correlations in the superconductivity of La3Ni2O7 — •Siheon Ryee1, Niklas Witt1,2, and Tim Wehling1,2 — 1Universität Hamburg, Hamburg, Germany — 2The Hamburg Centre for Ultrafast Imaging, Hamburg, Germnay
The recent discovery of superconductivity in La3Ni2O7 with Tc ≃ 80 K under high pressure opens up a new route to high-Tc superconductivity. This material realizes a bilayer square lattice model featuring a strong interlayer hybridization unlike many unconventional superconductors. A key question in this regard concerns how electronic correlations driven by the interlayer hybridization affect the low-energy electronic structure and the concomitant superconductivity. Here, we demonstrate using a cluster dynamical mean-field theory that the interlayer electronic correlations (IECs) induce a Lifshitz transition resulting in a change of Fermi surface topology. By solving an appropriate gap equation, we further show that the dominant pairing instability (intraorbital s-wave/interorbital dx2−y2-wave) is enhanced by the IECs. The underlying mechanism is the quenching of a strong ferromagnetic channel, resulting from the Lifshitz transition driven by the IECs. Our finding establishes the role of IECs in La3Ni2O7 and potentially paves the way to designing higher-Tc nickelates.
Keywords: bilayer nickelate; La3Ni2O7; dynamical mean-field theory; electronic correlations; superconductivity