Topotactic Hydrogen in Nickelate Superconductors and Akin Infinite-Layer Oxides ABO_{2}

Superconducting nickelates appear to be difficult to synthesize. Since the chemical reduction of ABO_{3} [rare earth (A), transition metal (B)] with CaH_{2} may result in both ABO_{2} and ABO_{2}H, we calculate the topotactic H binding energy by density functional theory (DFT). We find intercalating...

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Bibliographic Details
Published in:Physical review letters 2020-04, Vol.124 (16), p.166402-166402
Main Authors: Si, Liang, Xiao, Wen, Kaufmann, Josef, Tomczak, Jan M, Lu, Yi, Zhong, Zhicheng, Held, Karsten
Format: Article
Language:English
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Summary:Superconducting nickelates appear to be difficult to synthesize. Since the chemical reduction of ABO_{3} [rare earth (A), transition metal (B)] with CaH_{2} may result in both ABO_{2} and ABO_{2}H, we calculate the topotactic H binding energy by density functional theory (DFT). We find intercalating H to be energetically favorable for LaNiO_{2} but not for Sr-doped NdNiO_{2}. This has dramatic consequences for the electronic structure as determined by DFT+dynamical mean field theory: that of 3d^{9} LaNiO_{2} is similar to (doped) cuprates, 3d^{8} LaNiO_{2}H is a two-orbital Mott insulator. Topotactic H might hence explain why some nickelates are superconducting and others are not.
ISSN:1079-7114
DOI:10.1103/PhysRevLett.124.166402