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arXiv · 2409.06695

Ternary nickel hydrides: a new platform for unconventional superconductivity and quantum magnetism

Mateusz Domanski·Antonio Santacesaria·Paolo Barone·Jose Lorenzana·Wojciech Grochala
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Abstract

In this letter, we propose ternary nickel hydrides MNiH2 (M = Li, Na) as new materials that mimic cuprate physics but have important differences and interesting properties. Ni-H bands are wider than in oxides due to shorter bond lengths and covalency is larger than in Ni oxides which leads to a large scale of magnetic interactions. The charge transfer energy is smaller than in LaNiO2 which in cuprates translates to a larger Tc. We notice the formation of the electride band close to the Fermi surface which appears due to H vacancy along the c lattice vector. The considerable difference with cuprates arises from dz2 orbitals hybridization with interstitial orbitals allowing charge transfer to an apical vacancy state and self-doping the cuprate like Ni dx2-y2 H s antibonding bands which suggests that stoichiometric NaNiH2 may already be metallic and superconducting.

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Mateusz Domanski, Antonio Santacesaria, Paolo Barone, Jose Lorenzana, Wojciech Grochala. 2024-09-10. Ternary nickel hydrides: a new platform for unconventional superconductivity and quantum magnetism. https://doi.org/10.1103/physrevb.111.165137

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