Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Nickelates I
TT 5.2: Talk
Monday, March 18, 2024, 09:45–10:00, H 3007
Electronic correlations and superconducting instability in La3Ni2O7 under high pressure — Frank Lechermann, •Jannik Gondolf, Steffen Bötzel, and Ilya M. Eremin — Institut für Theoretische Physik III, Ruhr-Universität Bochum, D-44780 Bochum, Germany
Motivated by the report of superconductivity in bilayer La3Ni2O7 at high pressure, we examine the interacting electrons in this system. First-principles many-body theory is utilized to study the normal-state electronic properties. Below 100 K, a multi-orbital non-Fermi liquid state resulting from loss of Ni-ligand coherence within a flat-band dominated low-energy landscape is uncovered. The incoherent low-temperature Fermi surface displays strong mixing between Ni-dz2 and Ni-dx2−y2 orbital character. In a model-Hamiltonian picture, spin fluctuations originating mostly from the Ni-dz2 orbital give rise to strong tendencies towards a superconducting instability with B1g or B2g order parameter. The dramatic enhancement of Tc in pressurized La3Ni2O7 is due to stronger Ni-dz2 correlations compared to those in the infinite-layer nickelates.
Keywords: unconventional Superconductiviy; high-Tc; strong correlations