Source capture
Authors Haoran Ji, Zheyuan Xie, Yaqi Chen, Guangdi Zhou, Longxin Pan, Heng Wang, Haoliang Huang, Jun Ge, Yi Liu, Guang-Ming Zhang, Ziqiang Wang, Qi-Kun Xue, Zhuoyu Chen, Jian Wang
arXiv / Publisher https://arxiv.org/abs/2508.16412
PDF https://arxiv.org/pdf/2508.16412
Relevance score 5.554
Primary category cond-mat.supr-con
Published 2026-03-05
Research paradigm Experimental
Sample form Thin Film

Summary

The research team conducted electrical transport measurements on (La, Pr, Sm)3Ni2O7 double-layer nickelate thin films and discovered a time-reversal symmetry breaking superconducting state accompanied by electronic glass behavior. This superconducting state emerges in the low-temperature regime near zero resistance, exhibiting three prominent features: first, an unconventional magnetoresistance hysteresis that directly evidences time-reversal symmetry breaking and remains robust under different magnetic field orientations, fundamentally distinct from vortex pinning or long-range magnetic order; continuous oxygen reduction simultaneously weakens both superconductivity and the hysteresis, revealing their connection to specific Ni 3d electronic orbitals. Second, the current–voltage response demonstrates magnetic history dependence and non-reciprocity under zero field, further confirming spontaneous intrinsic time-reversal symmetry breaking. Third, the resistance exhibits slow logarithmic relaxation after removing the magnetic field, a hallmark of glassy dynamics. These phenomena reveal for the first time in nickel-based superconductors a superconducting state that simultaneously possesses spontaneous time-reversal symmetry breaking and intrinsic glassy characteristics, providing significant phenomenological and conceptual breakthroughs for understanding the mechanism of high-temperature superconductivity.

Materials

Methods

Keywords

  • time reversal symmetry breaking
  • electronic glass
  • superconducting glass state
  • magnetoresistance hysteresis
  • non reciprocal transport
  • logarithmic resistance relaxation
  • spin glass
  • orbital selectivity

Highlights

  • The unconventional magnetoresistance hysteresis is robust under different magnetic field orientations and differs fundamentally from trapped vortices or long-range-ordered magnetism.
  • Successive oxygen reductions simultaneously weaken both the superconductivity and hysteresis, revealing their mutual connections to selective electronic orbitals.
  • The non-reciprocal current-voltage response is magnetic field history-dependent, exhibiting highly effective field-tunability and memory effect.
  • Logarithmically slow resistance relaxations upon removal of magnetic field are hallmarks of glassy dynamics.

Conclusions

  • Through electrical transport study, we report the discovery of time-reversal symmetry breaking superconductivity with electronic glass in bilayer nickelate (La,Pr,Sm)3Ni2O7 films.
  • It emerges in the lower-temperature regime of superconducting transition to the zero-resistance state, and is captured by three remarkable characteristics: unconventional magnetoresistance hysteresis, magnetic field history-dependence and zero-field non-reciprocity in current-voltage responses, and logarithmically slow resistance relaxations.
  • Our findings uncover an unprecedented superconducting state in the nickelate superconductors, providing phenomenological and conceptual advances for future research on high-Tc superconductivity.

Main claims

  • Unconventional magnetoresistance hysteresis provides direct evidence of time-reversal symmetry breaking, distinct from trapped vortices or long-range magnetism.
    • Evidence: abstract: 'Unconventional magnetoresistance hysteresis, the direct evidence of TRS breaking',full_text: hysteresis observed under both out-of-plane and in-plane fields, with coalescing minima at zero field
  • Magnetic field history-dependence and zero-field non-reciprocity in I-V responses substantiate intrinsic and spontaneous TRS breaking.
    • Evidence: abstract: 'Magnetic field history-dependence and zero-field non-reciprocity',full_text Fig. 3a-f show clear deviation between V(I+) and |V(I-)| at zero field
  • Logarithmically slow resistance relaxations after field removal are hallmarks of glassy dynamics.
    • Evidence: abstract: 'Logarithmically slow resistance relaxations upon the removal of magnetic field, the hallmarks of glassy dynamics',full_text Fig. 5b-g show R_S(τ) ∝ -β log10 τ below 28K
  • Successive oxygen reductions simultaneously weaken both superconductivity and hysteresis, revealing connection to selective electronic orbitals (likelyNi 3dx2-y2).
    • Evidence: abstract: 'Successive oxygen reductions simultaneously weaken both the superconductivity and hysteresis',full_text Fig. 4a-d show systematic suppression with decreasing oxygen content

Workflow

  • film_synthesis — High-quality single-crystalline films prepared.
    • Materials: (La,Pr,Sm)3Ni2O7 thin films with various compositions
    • Methods: gigantic-oxidative atomic-layer-by-layer epitaxy (GAE); on SrLaAlO4 (001) substrates
    • Observations: RHEED oscillations confirm layer-by-layer growth; XRD confirms pure phase
  • transport_measurements — Three key signatures of TRS breaking glass superconductivity observed.
    • Materials: three compositions: La1.95Pr1.05Ni2O7, La2.85Pr0.15Ni2O7, La2.46Pr0.24Sm0.3Ni2O7
    • Methods: four-electrode transport; magnetoresistance; Hall effect; current-voltage (I-V) characteristics
    • Observations: BKT transition, T_c^onset ≈48 K, T_c^zero ≈17K; hysteretic magnetoresistance below 26K; non-reciprocal I-V; logarithmic resistance relaxation