An electron is usually considered to have only one form of kinetic energy, but could it have more, for its spin and charge, by exciting other electrons? In one dimension (1D), the physics of interacting electrons is captured well at low energies by the Tomonaga-Luttinger model, yet little has been observed experimentally beyond this linear regime. Here, we report on measurements of many-body modes in 1D gated wires using tunneling spectroscopy. We observe two parabolic dispersions, indicative of separate Fermi seas at high energies, associated with spin and charge excitations, together with the emergence of two additional 1D “replica” modes that strengthen with decreasing wire length. The interaction strength is varied by changing the amount of 1D intersubband screening by more than 45%. Our findings not only demonstrate the existence of spin-charge separation in the whole energy band outside the low-energy limit of the Tomonaga-Luttinger model but also set a constraint on the validity of the newer nonlinear Tomonaga-Luttinger theory.

中文翻译：

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在强相关的一维导体中观察单独的自旋和电荷费米海

一个电子通常被认为只有一种形式的动能，但它是否可以通过激发其他电子来获得更多的动能，因为它的自旋和电荷？在一维 (1D) 中，Tomonaga-Luttinger 模型在低能量下很好地捕获了相互作用电子的物理特性，但在此线性范围之外几乎没有观察到实验。在这里，我们报告了使用隧道光谱法测量一维门控线中的多体模式。我们观察到两个抛物线色散，表明高能下的单独费米海，与自旋和电荷激发相关，同时出现了两个额外的 1D“复制”模式，这些模式随着导线长度的减少而增强。通过将 1D 子带间筛选量改变 45% 以上来改变相互作用强度。