Source zotero
Authors Menghan Liao
arXiv / Publisher Not available in this batch.
PDF Not available in this batch.
Relevance score Not available in this batch.
Primary category Not available in this batch.
Published 2026-01-01
Research paradigm Unknown
Sample form Unknown

Summary

Bosonic Phases across the Superconductor-Insulator Transitions in Infinite-Layer Samarium Nickelate

Materials

Not available in this batch.

Methods

Not available in this batch.

Keywords

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Highlights

Not available in this batch.

Conclusions

Not available in this batch.

Main claims

  • Magnetoresistance oscillations with period h/2e provide direct evidence of 2e Cooper pairing in nickelate superconductors.
    • Evidence: Figure 2: clear oscillations with period corresponding to one flux quantum per honeycomb lattice cell,oscillation amplitude independent of excitation current below 200 nA
  • The superconductor-insulator transition is driven by enhanced superconducting fluctuations, with Cooper pairs persisting across the transition.
    • Evidence: Tc onset decreases only mildly from ≈20 K to ≈15 K while sheet resistance increases 20-fold,MR oscillations with h/2e period persist in the insulating state (S1 No.4),kinks in Rs(T) curves indicate Cooper pairing within islands
  • Two types of anomalous metallic states are observed: one at finite magnetic fields and one at zero magnetic field, both exhibiting intrinsic resistance saturation.
    • Evidence: Figure 3: resistance saturation under applied field (S1 No.2),Figure 4: resistance saturation at zero field (S1 No.3),saturation independent of excitation current and RC filters
  • The anomalous metallic state at finite field is consistent with quantum creep of vortices.
    • Evidence: Field-dependent resistance at 0.26 K fits quantum creep model over 0.5 T to 2 T,suppression of Hall signal at low temperatures

Workflow

  • Sample preparation — Nanopatterning via RIE through AAO masks enhances superconducting fluctuations and drives a superconductor-insulator transition.
    • Materials: Sm0.95−xEuxCa0.05NiO2 films; (LaAlO3)0.3(Sr2TaAlO6)0.7 substrates; AAO masks
    • Methods: pulsed laser deposition (PLD); topotactic reduction; AAO mask transfer; reactive ion etching (RIE)
    • Observations: pristine film superconducting with Tc onset ≈20 K and zero resistance ≈7.5K; increasing etching time increases disorder and suppresses superconductivity
  • Transport measurement — Cooper pairs are involved in transport across the SIT, and bosonic phases (AM state, strange metal) emerge from phase fluctuations.
    • Methods: electrical transport measurements (Rs vs T, Rs vs H); magnetoresistance (MR) measurements
    • Observations: MR oscillations with period ≈0.23 T = h/2e per network unit cell; resistance saturation to finite values at low T (anomalous metallic states); linear Rs(T) over wide T range (bosonic strange metal)
  • Data analysis and interpretation — Two types of anomalous metallic states are observed, attributed to quantum vortex creep (finite field) and Ohmic dissipation of phase fluctuations (zero field).
    • Methods: background subtraction of MR; coherence length estimation from oscillation amplitude; quantum creep model fitting
    • Observations: phase coherence length ≈65 nm below 0.5K; oscillation amplitude inconsistent with Little-Parks effect, consistent with JJA; field-dependent resistance fits quantum creep model