Evidence of universal spectral collapse at a marginal dynamical regime

摘要

该研究提出，强关联材料中非相干电子态并非源于无序或材料特定机制，而是由竞争涨落导致的自生动力学无序所产生。在这一边际动力学区域中，电子动力学与时间依赖散射自然耦合，导出谱函数形式ρ(z)=exp(-z²/4)D_ν(z)，其中z为标度能量，D_ν为抛物柱面函数，且ν=-1/2固定。通过对铜氧化物Nd_2-xCe_xCuO₄和Bi₂Sr₂CaCu₂O₈₊δ、Kagome金属CsCr₃Sb₅以及双层镍酸盐La₃Ni₂O₇的角分辨光电子能谱（ARPES）能量分布曲线进行独立标度后，所有数据集坍塌至同一普适曲线，仅振幅与能量标度因材料而异。该光谱坍塌表明低能区域中晶格几何、能带结构与化学成分等微观细节不再相关，呈现固定点般的动力学行为。这一结果建立了跨多种强关联材料的连续主导型ARPES谱的统一定量框架。

材料

• Nd_2-xCe_xCuO₄ (NCCO)
• Bi₂Sr₂CaCu₂O₈+δ (Bi₂₂₁₂)
• CsCr₃Sb₅ (Kagome)
• La₃Ni₂O₇

方法

• ARPES
• theoretical modeling using path integral
• parabolic cylinder function fitting
• scaling analysis

关键词

• universal spectral collapse
• marginal dynamical regime
• incoherent spectra
• non markovian dynamics
• parabolic cylinder function
• fixed point behavior
• strongly correlated materials

亮点

• The scaling function ρ(z) = exp(-z2/4) D_ν(z) with ν=-1/2 describes the incoherent spectra quantitatively.
• The collapse is robust across cuprate, nickelate, and Kagome compounds, despite differences in material properties.
• The observed universality indicates self-generated dynamical disorder from competing fluctuations, not extrinsic disorder.

结论

• After rescaling, the datasets collapse onto a single universal curve characterized by a fixed parabolic-cylinder order ν = -1/2.
• This indicates a fixed-point-like regime in which microscopic details such as lattice geometry, band structure, and chemical composition become irrelevant at low energies.
• These results establish a unified and quantitative framework for continuum-dominated ARPES spectra across diverse strongly correlated materials.

主要论断

• Incoherent ARPES spectra from cuprates, nickelate, and Kagome compounds collapse onto a single universal curve described by ρ(z) = exp(-z²/4) D_ν(z) with ν = -1/2.
  • 证据: abstract: 'After rescaling, the datasets collapse onto a single universal curve characterized by a fixed parabolic-cylinder order ν = -1/2',full_text Fig. 1 shows scaled data from Bi₂₂₁₂, NCCO, nickelate, Kagome falling on the same theoretical curve
• This universal spectral form arises from a marginal dynamical regime with self-generated dynamical disorder from competing fluctuations, characterized by non-Markovian temporal correlations.
  • 证据: abstract: 'incoherent spectra arise from self-generated dynamical disorder associated with competing fluctuations',full_text: 'the Gaussian temporal factor e-η²t²/2 reflects intrinsically non-Markovian dynamics'
• The observed spectral collapse indicates a fixed-point-like regime where microscopic details (lattice geometry, band structure, composition) become irrelevant at low energies.
  • 证据: abstract: 'observed spectral collapse indicates a fixed-point-like regime',full_text: 'microscopic details such as lattice geometry, band structure, and chemical composition become irrelevant at low energies'

研究流程

• data_collection — Selected ARPES data represent the incoherent continuum regime.
  • 材料: ARPES energy distribution curves from cuprates Nd_2-xCe_xCuO₄ (NCCO), Bi₂Sr₂CaCu₂O₈₊δ (Bi₂₂₁₂), Kagome metal CsCr₃Sb₅, and double-layer nickelate La₃Ni₂O₇
  • 方法: literature data extraction
  • 观察: Spectra dominated by broad continuum features rather than sharp quasiparticle peaks
• fitting_and_scaling_analysis — The universal scaling function quantitatively describes incoherent spectra across materials.
  • 材料: experimentally derived spectral functions I(ε,T)
  • 方法: fitting to ρ(ε) * f(ε,T) with ρ(z) = a exp(-z²/4) D_ν(z); auxiliary parabolic cylinder components included when needed
  • 观察: All datasets collapse onto the universal form after rescaling