Polaritons are light-matter quasiparticles that govern the optical response of quantum materials at the nanoscale, enabling on-chip communication and local sensing. Here, we report Landau-phonon polaritons (LPPs) in magnetized charge-neutral graphene encapsulated in hexagonal boron nitride (hBN). These quasiparticles emerge from the interaction of Dirac magnetoexciton modes in graphene with the hyperbolic phonon polariton modes in hBN. Using infrared magneto-nanoscopy, we reveal the ability to completely halt the LPP propagation in real space at quantized magnetic fields, defying the conventional optical selection rules. The LPP-based nanoscopy also tells apart two fundamental many-body phenomena: the Fermi velocity renormalization and field-dependent magnetoexciton binding energies. Our results highlight the potential of magnetically tuned Dirac heterostructures for precise nanoscale control and sensing of light-matter interaction.

中文翻译：

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Dirac 异质结构中的 Landau-phonon 极化激元


极化激元是轻物质准粒子，在纳米尺度上控制量子材料的光学响应，实现片上通信和局部传感。在这里，我们报道了封装在六方氮化硼 （hBN） 中的磁化电荷中性石墨烯中的朗道声子极化激元 （LPP）。这些准粒子来自石墨烯中的 Dirac 磁激子模式与 hBN 中的双曲声子极化激子模式的相互作用。使用红外磁纳米显微镜，我们揭示了在量子化磁场下完全停止 LPP 在真实空间中传播的能力，打破了传统的光学选择规则。基于 LPP 的纳米显微镜还区分了两个基本的多体现象：费米速度重整化和场依赖性磁激子结合能。我们的结果突出了磁调谐 Dirac 异质结构在精确纳米级控制和传感光-物质相互作用方面的潜力。