Weakly anisotropic superconductivity of Pr₄Ni₃O₁₀ single crystals

Summary

This study performed in situ high-pressure angle-dependent electrical transport measurements on Pr₄Ni₃O₁₀ single crystals using a custom diamond anvil cell rotator, confirming their superconducting anisotropy. Under a pressure of 50.2 GPa, the sample underwent a superconducting transition with a critical temperature of approximately 31 K. B_y measuring the upper critical fields perpendicular and parallel to the ab-plane, an anisotropy parameter γ of about 1.6 was obtained, which decreased with increasing temperature and approached 1 near the superconducting critical temperature. Fitting with the Ginzburg-Landau model yielded zero-temperature upper critical fields parallel and perpendicular to the ab-plane of 89.9 T and 57.3 T, respectively, and coherence lengths along the ab-plane and c-axis of 2.4 nm and 1.5 nm, respectively. Comparison with cuprate and iron-based superconductors revealed that the anisotropic behavior of Pr₄Ni₃O₁₀ conforms to a two-band model, where in-plane quantum confinement induces interlayer coherence, resulting in three-dimensional superconducting characteristics. This study not only confirms the existence of anisotropic superconductivity in bulk Ruddlesden-Popper nickelates but also provides critical insights into the role of dimensionality in the mechanism of high-temperature superconductivity.

Materials

• Pr₄Ni₃O₁₀

Methods

• In situ high-pressure angle-dependent electrical transport
• Diamond anvil cell
• Ginzburg-Landau fitting
• WHH model
• GGA+U
• DFT+eDMFT

Keywords

• superconducting anisotropy
• upper critical field
• two band model
• three dimensional superconductivity
• interlayer coherence

Highlights

• This study not only confirms the existence of anisotropic superconductivity in bulk Ruddlesden-Popper nickelates but also provides critical insight into the role of dimensionality in high-temperature superconductivity.
• The weak anisotropy is comparable to that of iron-based superconductors, despite structural similarities with cuprates.

Conclusions

• The anisotropy parameter γ is about 1.6, decreasing with increasing temperature and approaches 1 near T_c.
• Pr₄Ni₃O₁₀ conforms to a two-band model, where intralayer quantum confinement induces interlayer coherence, resulting in three-dimensional superconducting characteristics.
• Zero-temperature upper critical fields are 89.9 T (parallel) and 57.3 T (perpendicular), with coherence lengths of 2.4 nm (in-plane) and 1.5 nm (out-of-plane).

Main claims

• Pr₄Ni₃O₁₀ single crystals show weakly anisotropic superconductivity with anisotropy parameter γ ≈ 1.6 at zero temperature.
  • Evidence: Abstract: 'an anisotropy parameter γ of about 1.6 was obtained'
• The anisotropic behavior conforms to a two-band model where in-plane quantum confinement induces interlayer coherence, leading to 3D superconductivity.
  • Evidence: Abstract: 'the anisotropic behavior of Pr₄Ni₃O₁₀ conforms to a two-band model, where in-plane quantum confinement induces interlayer coherence, resulting in three-dimensional superconducting characteristics'

Workflow

• Sample synthesis
  • Materials: Pr₄Ni₃O₁₀ single crystals
  • Methods: Vertical optical-image floating zone method; High oxygen pressure (140-150 bar)
  • Observations: Monoclinic crystal structure, high quality confirmed by XRD and EDS
• High-pressure transport with rotation
  • Materials: Single crystals; Diamond anvil cell (DAC)
  • Methods: In situ high-pressure angle-dependent electrical transport; Custom DAC rotator; Helium pressure transmitting medium
  • Observations: Superconducting transition at approximately 31K; Angular dependence of upper critical field
• Data analysis — Pr₄Ni₃O₁₀ exhibits weakly anisotropic superconductivity consistent with 3D two-band model
  • Materials: Resistance vs temperature at various angles and fields
  • Methods: Ginzburg-Landau (GL) model fitting; Werthamer-Helfand-Hohenberg (WHH) model
  • Observations: Anisotropy parameter γ ≈ 1.6; Coherence lengths: ξab(0)=2.4 nm, ξc(0)=1.5 nm