Topotactical Hydrogen Induced Single-Band d-Wave Superconductivity in La2NiO4

Abstract

La2NiO4 is an antiferromagnetic insulator with a structural resemblance to its cuprate counterpart, La2CuO4. However, La2CuO4 has a Cu2+ or 3d9 electronic configuration that needs to be hole or electron doped for superconductivity, whereas La2NiO4 is 3d8 with divalent Ni2+. Making a cuprate analog through conventional electron doping is impractical due to the rarity of tetravalent substituents for trivalent La. Here, we propose an alternative route: intercalating topotactical hydrogen, which is possible through electric-field-controlled protonation and transforms La2NiO4 into a 3dx2−y2 single-band two-dimensional antiferromagnetic Mott insulator analogous to La2CuO4. This we find through density-functional theory and dynamical mean-field theory calculations. The furthergoing dynamical vertex approximation predicts that H−La2NiO4 can host d-wave superconductivity under 15% hole doping with a critical temperature above 20 K. Our findings not only suggest a new method for tuning the electronic structure of layered nickelates but also provide theoretical evidence for a new nickelate superconductor, awaiting experimental synthesis.

Source-reported materials — not catalogue approval

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