Quantum engineering of Landau levels using isotopes in graphene-like graphite

Landau levels are cornerstones of a wide range of quantum phenomena and applications. Understanding the impact of the gauge field, or pseudomagnetic field, on the electronic structure of 2D materials is critical for manipulating Landau electrodynamics. Although extensive theoretical and experimental studies have been carried out to probe pseudomagnetic field in graphene, most of them have been focused on the strain- and substrate-engineering methods and magnetotransport properties. Here, we present using graphite as a unique material testbed for realizing isotope-induced pseudomagnetic field. Using magneto-Raman spectroscopy, we show that pure C12 graphite and C13-doped graphite both exhibit graphene-like Landau level transitions. Remarkably, we demonstrate that C13-doping leads to splitting of the Landau level transitions, a signature of pseudomagnetic field on the scale of 0.2 T. Moreover, the split Landau level transitions selectively couple with the G band phonon in distinct energy ranges. Our results highlight isotope doping as a feasible material engineering method of creating pseudomagnetic field and tuning magneto-optical properties in 2D quantum materials.朗道能级（Landau levels）是一系列量子现象与应用的核心基石。探究规范场或赝磁场对二维（2D）材料电子结构的影响，对于调控朗道电动力学至关重要。尽管学界已开展大量理论与实验研究以探测石墨烯中的赝磁场，但此类研究大多聚焦于应变工程与衬底工程方法，以及磁输运性质。本文提出以石墨作为独特的材料测试平台，用以实现同位素诱导的赝磁场。借助磁拉曼光谱技术，我们发现纯C12石墨与掺C13石墨均展现出类石墨烯的朗道能级跃迁现象。值得注意的是，我们证实掺C13会引发朗道能级跃迁的劈裂，这是0.2特斯拉量级赝磁场的特征信号。此外，劈裂后的朗道能级跃迁会在不同能量范围内与G带声子发生选择性耦合。我们的研究结果表明，同位素掺杂是一种可行的材料工程手段，可用于在二维量子材料中构建赝磁场并调控其磁光性质。