来源 自动抓取
作者 Shuxiang Xu, Guangdi Zhou, Hao Wang, Tianyi Wu, Wei Wang, Liyu Shi, Dong Wu, Haoliang Huang, Xinbo Wang, Jinfeng Jia, Qi-Kun Xue, Zhuoyu Chen, Tao Dong, Nanlin Wang
arXiv / 出版方 http://arxiv.org/abs/2604.04421v1
PDF https://arxiv.org/pdf/2604.04421v1
相关度评分 5.129
主分类 本批次暂无数据。
发布日期 本批次暂无数据。
研究范式 实验研究
样品形态 薄膜

摘要

该研究通过结合线性太赫兹时域光谱与三阶谐波产生技术，系统探测了压缩应变(La,Pr)3Ni2O7薄膜的超导配对对称性及正常态赝能隙。线性太赫兹光谱观测到超导转变温度以下低频谱权重的显著抑制，伴随弱相干峰以及趋近零温时仍存在的较大剩余电导，与无序s±波配对图像一致。非线性三阶谐波信号在进入超导态后急剧增强，但其响应在超导转变温度以上持续存在，并在约100K处出现扭折，结合角分辨光电子能谱在同类薄膜中观测到的类似温度尺度，将其归因于正常态赝能隙。研究确立了(La,Pr)3Ni2O7为具有s±波类配对的体超导体，且该超导态与另一有序态共存并可能相互竞争，为探索超越铜基和铁基的非常规超导机制提供了新平台。

材料

方法

  • terahertz time-domain spectroscopy
  • third-harmonic generation

关键词

亮点

  • The superconducting gap scale is above the measurement window, with about 65% of carriers remaining uncondensed at 2 K.
  • The London penetration depth is approximately 620 nm, implying a strongly reduced superfluid density.

结论

  • Linear THz spectroscopy reveals a bulk superconducting response with a weak coherence peak and large residual conductivity, consistent with disordered s±-wave pairing.
  • The nonlinear third-harmonic signal persists above Tc, attributed to a normal-state pseudogap.

主要论断

  • (La,Pr)3Ni2O7 thin films exhibit bulk superconductivity with disordered s±-wave pairing
    • 证据: Linear THz shows suppression of spectral weight, weak coherence peak, large residual conductivity, large penetration depth ≈620 nm
  • An anomalous normal-state pseudogap emerges above Tc, evidenced by persistent third-harmonic signal with kink at ≈100K
    • 证据: THG signal persists above Tc and shows reproducible kink near 100 K, matching ARPES pseudogap temperature

研究流程

  • Sample growth and characterization
    • 材料: (La,Pr)3Ni2O7 thin films on SrLaAlO4 substrates
    • 方法: Gigantic-Oxidative Atomic-Layer-by-Layer Epitaxy (GAE)
  • Linear terahertz spectroscopy — Bulk superconducting response with s±-wave pairing in disordered limit
    • 材料: THz time-domain spectroscopy setup
    • 方法: Fresnel analysis; Temperature-dependent conductivity extraction
    • 观察: Suppression of low-frequency spectral weight below Tc; Weak coherence peak near Tc; Large residual conductivity at 2K; London penetration depth ≈620 nm
  • Nonlinear THz third-harmonic generation — Pseudogap phase above Tc suggested by nonlinear response
    • 材料: Narrowband multicycle THz pulses; Band-pass filters
    • 方法: Third-harmonic generation; Electro-optic sampling
    • 观察: THG enhancement below Tc; THG persists above Tc with kink at ≈100K