When Bloch electrons in a solid are exposed to a strong optical field, they are coherently driven in their respective bands where they acquire a quantum phase as the imprint of the band shape. If an electron approaches an avoided crossing formed by two bands, it may be split by undergoing a Landau-Zener transition. We here employ subsequent Landau-Zener transitions to realize strong-field Bloch electron interferometry, allowing us to reveal band structure information. In particular, we measure the Fermi velocity (band slope) of graphene in the vicinity of the K points as $(1.07\pm 0.04)\mathrm{nm}{\mathrm{fs}}^{-1}$. We expect strong-field Bloch electron interferometry for band structure retrieval to apply to a wide range of material systems and experimental conditions, making it suitable for studying transient changes in band structure with femtosecond temporal resolution at ambient conditions.

中文翻译：

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用于能带结构检索的强场布洛赫电子干涉仪

当固体中的布洛赫电子暴露于强光场时，它们在各自的能带中被相干地驱动，在那里它们获得量子相作为能带形状的印记。如果电子接近由两个能带形成的避免交叉，它可能会因经历朗道-齐纳跃迁而分裂。我们在这里利用随后的朗道-齐纳跃迁来实现强场布洛赫电子干涉测量，使我们能够揭示能带结构信息。特别地，我们测量了 K 点附近石墨烯的费米速度（能带斜率）：$（1.07\pm 0.04）\mathrm{纳米}{\mathrm{FS}}^{-1}$。我们期望用于能带结构反演的强场布洛赫电子干涉技术能够应用于广泛的材料系统和实验条件，使其适合在环境条件下以飞秒时间分辨率研究能带结构的瞬态变化。