Ultrafast Magneto-Pressure Spectroscopy and Control of Correlated Phases in a Trilayer Nickelate

Summary

This study developed an ultrafast magneto-pressure optical spectroscopy platform capable of operating simultaneously at pressures up to 40 GPa, magnetic fields up to 7 T, and temperatures as low as 5 K, and applied it to investigate the evolution of quasiparticle dynamics under magnetic pressure in the trilayer nickelate Pr₄Ni₃O₁₀. The experiments revealed a pronounced critical slowing down of quasiparticle relaxation near the charge density wave (CDW) transition, which disappears upon the application of pressure. At higher pressures, the low-temperature relaxation time instead becomes longer, consistent with initial superconducting correlation signatures. However, a magnetic field as high as 7 T hardly alters the relaxation behavior, and no vortex-induced pre-bottleneck dynamics—robustly observed in bulk superconducting control samples—was detected, suggesting that any superconducting state under the present pressure conditions is not bulk-like but rather filamentary or strongly inhomogeneous. This magneto-pressure ultrafast capability opens a new pathway for addressing unresolved issues of pressure-induced superconductivity and intertwined orders in correlated quantum materials.

Materials

• Pr₄Ni₃O₁₀

Methods

• ultrafast pump-probe spectroscopy
• diamond anvil cell (DAC)
• magneto-cryostat
• ultrafast spectroscopy under high pressure and high magnetic field

Keywords

• critical slowing down
• charge density wave
• filamentary superconductivity
• vortex dynamics
• superconducting correlations

Highlights

• The developed ultrafast magneto-pressure spectroscopy platform operates up to 40 GPa, 7 T, and 5 K.
• No vortex-induced pre-bottleneck dynamics are detected, ruling out bulk superconductivity in the measured pressure range.
• First implementation of simultaneous high-pressure, high-magnetic-field, cryogenic femtosecond spectroscopy.

Conclusions

• A pronounced critical slowing down near the CDW transition disappears upon pressure application.
• At higher pressures, the low-temperature relaxation time lengthens, consistent with incipient superconducting correlations, but magnetic field dependence is negligible, suggesting filamentary or inhomogeneous superconductivity.
• The charge-density-wave transition shows critical slowing down that collapses under pressure.
• At higher pressures, relaxation lengthens at low temperature, suggesting incipient superconducting correlations.
• Absence of field dependence up to 7 T indicates any superconducting state is likely non-bulk or inhomogeneous.

Main claims

• The charge-density-wave order in Pr₄Ni₃O₁₀ is suppressed by applied pressure, and low-temperature relaxation dynamics lengthen at high pressures
  • Evidence: At₄.2 GPa, pronounced critical slowing down near CDW transition; at 38 GPa, no anomaly; relaxation time increases with pressure at 5K
• An_y superconductivity under pressure is not bulk, as no magnetic-field-dependent vortex dynamics are observed up to 7T
  • Evidence: ΔR/R remains unchanged at 14 GPa and 5 K for fields up to 7 T, in contrast to bulk Nb control sample
• Development of ultrafast magneto-pressure spectroscopy (up to 40 GPa, 7 T, 5 K) enables direct probing of quasiparticle dynamics under extreme conditions.
  • Evidence: Detailed description of setup and first application to Pr₄Ni₃O₁₀.
• The CDW transition in Pr₄Ni₃O₁₀ shows critical slowing down of QP relaxation, which collapses under applied pressure.
  • Evidence: Temperature-dependent ∆R/R maps at 4.2 GPa show pronounced slowing near 120 K; at 38 GPa no anomaly.
• At higher pressures, prolonged QP relaxation at low temperature is consistent with incipient superconducting correlations, but the negligible magnetic-field-dependence and absence of vortex-induced pre-bottleneck dynamics indicate non-bulk or filamentary superconductivity.
  • Evidence: No discernible change in ∆R/R with magnetic field up to 7 T; comparison to Nb sample shows clear field dependence.

Workflow

• Sample preparation and high-pressure setup — CDW critical slowing down collapses under pressure
  • Materials: Pr₄Ni₃O₁₀ single crystals; DAC with 400 μm culets
  • Methods: Ultrafast pump-probe with simultaneous pressure (up to 40 GPa) and magnetic field (up to 7 T)
  • Observations: ΔR/R temporal dynamics
• Data analysis — Superconductivity is not bulk; likely filamentary
  • Methods: Exponential fits; Rothwarf-Taylor model
  • Observations: High-pressure low-temperature prolonged relaxation; No magnetic field dependence up to 7T
• Sample Preparation — Pr₄Ni₃O₁₀ is suitable for high-pressure studies.
  • Materials: Pr₄Ni₃O₁₀ single crystals
  • Methods: floating zone growth under 140 bar O₂
  • Observations: high-quality single crystals with minimal stacking faults
• High-Pressure Diamond Anvil Cell (DAC) Setup — Ultrafast magneto-pressure spectroscopy is developed.
  • Materials: Pr₄Ni₃O₁₀ flake ≈120x120x10 µm³; Be-Cu DAC; Nujol mineral oil
  • Methods: loading in DAC with ruby manometers
  • Observations: sample loaded into magneto-cryostat
• Ultrafast Pump-Probe Spectroscopy — CDW critical slowing down collapses under pressure; at higher pressures, relaxation indicates incipient superconducting correlations.
  • Materials: Pr₄Ni₃O₁₀ in DAC
  • Methods: optical pump-probe reflectivity; 0.8 eV pump, 1.6 eV probe
  • Observations: ∆R/R dynamics; critical slowing down near CDW transition; prolonged relaxation at high pressure and low temperature
• Data Analysis and Modeling — The absence of magnetic-field-dependent dynamics suggests non-bulk superconductivity.
  • Materials: Pr₄Ni₃O₁₀
  • Methods: exponential fitting; Rothwarf-Taylor model; CDW gap extraction
  • Observations: CDW gap ∆CDW ≈ 23.9 meV at 0.3 µJ/cm²