Source zotero
Authors Hualei Sun, Mengwu Huo, Xunwu Hu, Jingyuan Li, Zengjia Liu, Yifeng Han, Lingyun Tang, Zhongquan Mao, Pengtao Yang, Bosen Wang, Jinguang Cheng, Dao-Xin Yao, Guang-Ming Zhang, Meng Wang
arXiv / Publisher https://www.nature.com/articles/s41586-023-06408-7
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Published 2023-09-21
Research paradigm Unknown
Sample form Unknown

Summary

Signatures of superconductivity near 80 K in a nickelate under high pressure

Materials

Not available in this batch.

Methods

Not available in this batch.

Keywords

Not available in this batch.

Highlights

Not available in this batch.

Conclusions

Not available in this batch.

Main claims

  • Superconductivity is observed in La3Ni2O7 single crystals under high pressure with onset Tc up to 80 K, above 14 GPa.
    • Evidence: Resistance drops sharply at ≈80 K under 14-43.5 GPa,Zero resistance observed in hydrostatic conditions,AC susceptibility shows diamagnetic response below 77 K at 25.2 GPa
  • The superconducting state emerges from a strange metal phase with linear temperature resistance up to 300 K.
    • Evidence: Normal state resistance above Tc is linear in temperature (T-linear) from Tc to 300K
  • The high-pressure Fmmm phase (Ni-O-Ni angle 180°) enables metallization of the interlayer dz2 σ-bonding bands, creating hole pockets around Γ and mimicking hole-doped bilayer cuprates.
    • Evidence: DFT calculations show dz2 bonding bands cross Fermi level at 29.5 GPa,Fermi surface topology changes from AP to HP

Workflow

  • crystal_growth — High-quality single crystals grown.
    • Materials: La3Ni2O7 single crystals
    • Methods: Vertical optical-image floating-zone furnace; Oxygen pressure 15 bar; 5-kW Xe arc lamp
    • Observations: Metallic at ambient, Fermi liquid behavior
  • high_pressure_electrical_transport — Superconductivity with onset Tc ≈80 K at pressures 14-43.5 GPa.
    • Materials: La3Ni2O7 single crystal (≈80×60×10 µm3)
    • Methods: Four-probe resistance in diamond anvil cell; Pressure medium: cBN+epoxy or KBr; PPMS for temperature and field
    • Observations: At >14 GPa, resistance drop at ≈80 K indicative of superconductivity; Linear normal state resistance (strange metal); Zero-resistance flat stage in KBr medium
  • magnetic_susceptibility — Diamagnetism confirms superconductivity.
    • Materials: La3Ni2O7 powder
    • Methods: AC magnetic susceptibility in diamond anvil cell; Mutual induction technique
    • Observations: Diamagnetic response below 77 K at 25.2 GPa
  • high_pressure_synchrotron_xrd — Structural phase transition associated with superconductivity.
    • Materials: Powdered La3Ni2O7
    • Methods: Synchrotron XRD at Beijing Synchrotron Radiation Facility; Rietveld refinement
    • Observations: Structural transition from Amam to Fmmm around 10 GPa; Ni-O-Ni angle reaches 180° in Fmmm phase
  • dft_calculations — Metallization of interlayer σ-bonding bands enables high-Tc superconductivity.
    • Materials: Crystal structures at 1.6 and 29.5 GPa
    • Methods: DFT+U (U=4 eV) using VASP; Projector augmented-wave method
    • Observations: At29.5 GPa: dz2 bonding bands cross Fermi level, forming small hole pocket; Fermi surface similar to hole-doped bilayer cuprates