来源 Zotero
作者 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 / 出版方 https://link.aps.org/doi/10.1103/j6hl-t2sh
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发布日期 2025-12-01
研究范式 未知
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摘要

Ultrafast optical evidence of coexisting density waves in bilayer nickelate La3Ni2O7

材料

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方法

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关键词

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亮点

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结论

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主要论断

  • 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.
    • 证据: 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.
    • 证据: Fast relaxation time τf remains constant above 39.8 µJ/cm2,SDW gap and T_SDW are still present at highest fluence

研究流程

  • sample_preparation — High-quality single crystals are obtained.
    • 材料: La3Ni2O7 single crystals
    • 方法: vertical optical image floating-zone method
    • 观察: well-defined (001) cleavage planes
  • ultrafast_optical_measurement — SDW and charge order are detected.
    • 材料: La3Ni2O7 single crystal (freshly cleaved surface)
    • 方法: ultrafast pump-probe spectroscopy; transient reflectivity; transient ellipticity
    • 观察: 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.
    • 材料: temporal data of ΔR/R and ellipticity
    • 方法: two-exponential fitting; Rothwarf-Taylor (RT) model; extraction of relaxation times and amplitudes
    • 观察: 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.
    • 材料: temperature-fluence data
    • 方法: compile T_SDW and T_DW from fittings
    • 观察: 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