Electronic structure, magnetic correlations, and superconducting pairing in the reduced Ruddlesden-Popper bilayer La${}_3$Ni${}_2$O${}_6$ under pressure: different role of $d_{3z^2-r^2}$ orbital compared with La${}_3$Ni${}_2$O${}_7$

Abstract

The recent discovery of superconductivity in bilayer La${}_3$Ni${}_2$O${}_7$ (327-LNO) under pressure stimulated much interest in layered nickelates. However, superconductivity was not found in another bilayer nickelate system, La${}_3$Ni${}_2$O${}_6$ (326-LNO), even under pressure. Using density functional theory and the random phase approximation (RPA), we systematically investigate 326-LNO under pressure. The large crystal-field splitting between the $e_g$ orbitals caused by the missing apical oxygen moves the $d_{3z^2-r^2}$ orbital farther away from the Fermi level, implying that the $d_{3z^2-r^2}$ orbital plays a less important role in 326-LNO than in 327-LNO. This also results in a smaller bandwidth for the $d_{x^2-y^2}$ orbital and a reduced energy gap for the bonding-antibonding splitting of the $d_{3z^2-r^2}$ orbital in 326-LNO, as compared to 327-LNO. Moreover, the in-plane hybridization between the $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals is found to be small in 326-LNO, while it is much stronger in 327-LNO. The weak inter-layer coupling suggests that $s_{\pm }$-wave pairing is unlikely in 326-LNO. The robust in-plane ferromagnetic coupling also suggests that d-wave superconductivity, which is usually caused by antiferromagnetic fluctuations of the $d_{x^2-y^2}$ orbital, is also unlikely in 326-LNO. These conclusions are supported by our many-body RPA calculations of the pairing behavior. Contrasting with the cuprates, for the bilayer cuprate HgBa${}_2$CaCu${}_2$O${}_6$, we find a strong "self-doping effect" of the $d_{x^2-y^2}$ orbital under pressure, with the charge of Cu being reduced by approximately 0.13 electrons from 0 GPa to 25 GPa. In contrast, we do not observe such a change in the electronic density in 326-LNO under pressure, establishing another important difference between the nickelates and the cuprates.

9 pages 6 figures

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Cited by in corpus (33)

• Visualization of Oxygen Vacancies and Self-doped Ligand Holes in La3Ni2O7-δ
• Sensitive dependence of pairing symmetry on Ni-$e_g$ crystal field splitting in the nickelate superconductor La${}_3$Ni${}_2$O${}_7$
• Prediction of $s^{\pm }$-wave superconductivity enhanced by electronic doping in trilayer nickelates La${}_4$Ni${}_3$O${}_{10}$ under pressure
• Non-Fermi Liquid and Hund Correlation in La${}_4$Ni${}_3$O${}_{10}$ under High Pressure
• Trilayer multi-orbital models of $\mathrm{L}{\mathrm{a}}_4\mathrm{N}{\mathrm{i}}_3{\mathrm{O}}_{10}$
• Antiferromagnetic Ground State, Charge Density Waves and Oxygen Vacancies Induced Metal-Insulator Transition in Pressurized La${}_3$Ni${}_2$O${}_7$
• Pair correlations of the hybridized orbitals in a ladder model for the bilayer nickelate La${}_3$Ni${}_2$O${}_7$
• Electronic instability, layer selectivity and Fermi arcs in La${}_3$Ni${}_2$O${}_7$
• Magnetism and superconductivity in the $t-J$ model of $L{a}_{3}N{i}_2{O}_7$ under multiband Gutzwiller approximation
• The $s^{\pm }$-Wave Superconductivity in the Pressurized La${}_4$Ni${}_3$O${}_{10}$
• Electronic structure, self-doping, and superconducting instability in the alternating single-layer trilayer stacking nickelates La${}_3$Ni${}_2$O${}_7$
• Origin of the density wave instability in trilayer nickelate La${}_4$Ni${}_3$O${}_{10}$ revealed by optical and ultrafast spectroscopy
• Magnetic phase diagram of a two-orbital model for bilayer nickelates varying doping
• Band Structure and Pairing Nature of La${}_3$Ni${}_2$O${}_7$ Thin Film at Ambient Pressure
• Spin-density wave and superconductivity in La${}_4$Ni${}_3$O${}_{10}$ under ambient pressure
• Electronic structures and multi-orbital models of La${}_3$Ni${}_2$O${}_7$ thin films at ambient pressure
• Impact of Pressure and Apical Oxygen Vacancies on Superconductivity in La${}_3$Ni${}_2$O${}_7$
• Strong-coupling study of the pairing mechanism in pressurized La${}_3$Ni${}_2$O${}_7$
• Interlayer interactions in ${\text{La}}_3{\text{Ni}}_2{\text{O}}_7$ under pressure: from $s^{\pm }$ to $d_{xy}$-wave superconductivity
• Magnetic Correlations and Pairing Tendencies of the Hybrid Stacking Nickelate Superlattice La${}_7$Ni${}_5$O${}_{17}$ (La${}_3$Ni${}_2$O${}_7$/La${}_4$Ni${}_3$O${}_{10}$) under Pressure
• Doping evolution of the normal state magnetic excitations in pressurized La3Ni2O7
• Electronic Structure, Magnetic and Pairing Tendencies of Alternating Single-layer Bilayer Stacking Nickelate La${}_5$Ni${}_3$O${}_{11}$ Under Pressure
• Possible Liquid-Nitrogen-Temperature Superconductivity Driven by Perpendicular Electric Field in the Single-Bilayer Film of La${}_3$Ni${}_2$O${}_7$ at Ambient Pressure
• Origin of the Diagonal Double-Stripe Spin-Density-Wave and Potential Superconductivity in Bulk La${}_3$Ni${}_2$O${}_7$ at Ambient Pressure
• Unifying Strain-driven and Pressure-driven Superconductivity in La${}_3$Ni${}_2$O${}_7$: Suppressed charge/spin density waves and enhanced interlayer coupling
• Unveiling the multiband metallic nature of the normal state in nickelate La3Ni2O7
• General trends of electronic structures, superconducting pairing, and magnetic correlations in the Ruddlesden-Popper nickelate $m$-layered superconductors La${}_{m+1}$Ni${}_m$O${}_{3m+1}$
• Superexchanges and Charge Transfer in the La${}_3$Ni${}_2$O${}_7$ Thin Films
• Pairing Symmetry Crossover from $d$-wave to $s_{\pm }$-wave in a Bilayer Nickelate Driven by Hund's Coupling and Crystal Field Splitting
• Pairing mechanism and superconductivity in pressurized La${}_5$Ni${}_3$O${}_{11}$
• Compressive Strain Turns $s^{\pm }$ into $d$-Wave Pairing in One-unit-cell La${}_3$Ni${}_2$O${}_7$ Thin Film Via Substrate-Induced Hole Doping
• Extended $s$-wave pairing from an emergent Feshbach resonance in bilayer nickelate superconductors
• Interplay of orbital-selective Mott criticality and flat-band physics in La${}_3$Ni${}_2$O${}_6$