Topotactical Hydrogen Induced Single-Band d -Wave Superconductivity in La₂ NiO 4

Summary

Topotactical Hydrogen Induced Single-Band d -Wave Superconductivity in La₂ NiO 4

Materials

Not available in this batch.

Methods

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Keywords

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Highlights

Not available in this batch.

Conclusions

Not available in this batch.

Main claims

• Topotactic hydrogen intercalation in La₂NiO₄ converts Ni₂+ (3d8) to Ni+ (3d9), creating a single-band dx2-y2 system analogous to cuprate parent compounds.
  • Evidence: DFT shows H at out-of-plane site is more stable; forms OH-,Band structure shows only dx2-y2 band at Fermi level; dz2 band shifts down,DMFT shows half-filled dx2-y2 band with large renormalization
• H-La₂NiO₄ can exhibit d-wave superconductivity with T_c up to 20 K under 15% hole doping, as predicted by DΓA.
  • Evidence: DΓA calculations show leading d-wave eigenvalue approaching 1 at low temperature for n=0.85 and n=0.80,Fermi surface evolution with doping consistent with cuprate-like behavior

Workflow

• structural_relaxation_and_aimd — H intercalation is stable and donates an electron, converting Ni₂+ to Ni+.
  • Materials: La₂NiO₄ unit cell with intercalated H
  • Methods: DFT structural relaxation (VASP, GGA-PBE); Ab initio molecular dynamics (AIMD) at 300K
  • Observations: H forms OH- with out-of-plane O; H-O bond length 0.99 Å (DFT), 0.99–1.05 Å (AIMD)
• electronic_structure_calculations — H-La₂NiO₄ is a single-band Mott insulator analogous to cuprates and can host d-wave superconductivity.
  • Materials: H-La₂NiO₄ (lowest energy structure)
  • Methods: DFT+U (U=2.8–2.92 eV from cRPA); Wannier projection; DMFT (continuous-time QMC); DΓA for superconductivity
  • Observations: Single-band dx2-y2 Fermi surface emerges; dz2 band shifts down; DMFT shows half-filled dx2-y2 band with effective mass m*/me ≈3.3; DΓA predicts d-wave superconductivity under ≈15% hole doping with T_c up to 20K