Source zotero
Authors Qi-Yi Wu, De-Yuan Hu, Chen Zhang, Mengwu Huo, Hao Liu, Bo Chen, Ying Zhou, Zhong-Tuo Fu, Chun-Hui Lv, Zi-Jie Xu, Hai-Long Deng, H. Y. Liu, Jun Liu, Yu-Xia Duan, Meng Wang, Jian-Qiao Meng
arXiv / Publisher https://link.aps.org/doi/10.1103/j6hl-t2sh
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Published 2025-12-01
Research paradigm Unknown
Sample form Unknown

Summary

Ultrafast optical evidence of coexisting density waves in bilayer nickelate La3Ni2O7

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

  • Two coexisting density waves are identified: a spin-density wave (SDW) at ≈140 K with electronic nematicity, and a distinct nonmagnetic charge order at ≈115 K.
    • Evidence: Transient reflectivity shows anomalies at 140 K and 115 K,Transient ellipticity confirms spin nature of the 140 K order,Spin relaxation time diverges near T_SDW
  • Differential optical control is demonstrated: the charge order is completely suppressed by ≈40 µJ/cm2, while the SDW persists even at 200 µJ/cm2.
    • Evidence: Fast relaxation time τf remains constant above 39.8 µJ/cm2,SDW gap and T_SDW are still present at highest fluence

Workflow

  • sample_preparation — High-quality single crystals are obtained.
    • Materials: La3Ni2O7 single crystals
    • Methods: vertical optical image floating-zone method
    • Observations: well-defined (001) cleavage planes
  • ultrafast_optical_measurement — SDW and charge order are detected.
    • Materials: La3Ni2O7 single crystal (freshly cleaved surface)
    • Methods: ultrafast pump-probe spectroscopy; transient reflectivity; transient ellipticity
    • Observations: two-exponential decay in ΔR/R; difference between left- and right-circularly polarized ellipticity below T_SDW
  • data_analysis — SDW gap opens at ≈140 K; charge order appears at ≈115 K.
    • Materials: temporal data of ΔR/R and ellipticity
    • Methods: two-exponential fitting; Rothwarf-Taylor (RT) model; extraction of relaxation times and amplitudes
    • Observations: As increases below T_SDW; τs diverges near T_SDW; τf shows downturn below 115K; SDW gap Δ_SDW(0)=69±4 meV from RT fit
  • phase_diagram_construction — Charge order is fragile; SDW is robust, demonstrating selective optical control.
    • Materials: temperature-fluence data
    • Methods: compile T_SDW and T_DW from fittings
    • Observations: T_DW suppressed to zero at ≈39.8 µJ/cm2; T_SDW decreases slowly to ≈70 K at 198.9 µJ/cm2; gap size reduces to 15 meV